Ich biete Unterricht, Förderkurse, Vorträge und Fortbildungskurse zu den Themen Naturkunde, Naturschutz, Artenvielfalt, Ökologie, Klimaschutz und Evolution an sowie Unterricht oder Vorträge zur Naturfotografie oder der Naturfilmerei. All dies entweder auf Honarbasis oder via Anstellung. Bitte entnehmen Sie weitere Informationen meinem Menüpunkt zum Thema Unterricht und Lehre. Selbstverständlich verfüge ich über Qualifikationsnachweise zu meinen diversen bisherigen Lehrtätigkeiten sowie meine fachliche Kompetenz. Bitte beachten Sie hierzu auch meinen Menüpunkt Curriculum Vitae.
Doch was sind eigentlich meine Themengebiete? Im Folgenden finden Sie interessante Fragestellungen aus meinen Kompetenzbereichen.
Was ist ein Ökosystem? Welche Ökosysteme sind gut untersucht, welche eher nicht? Wie gut kennt man die Artenvielfalt von Mikro-Lebensstätten in Deutschland, und was ist über deren biologische (ökologische) Zusammenhänge bekannt? Was ist denn eigentlich eine Art, was sind denn dann Zwillingsarten, und was versteht man gar unter einem Artenkomplex (kryptische Artengruppe)? Ist das Aussterben von Arten ein normaler Bestandteil der Evolution oder ist das Aussterben einer Art immer zwingend ein alamierender Hinweis auf eine (evtl. menschengemachte) Naturkatastrophe? Wieviele Arten aus allen Organismengruppen weltweit kennen wir, und wieviele in etwa kennen wir noch nicht? Warum kennen wir viele Arten, sogar in Deutschland, noch immer nicht? Wie erkennt man neue Arten, und wie ist eine sogenannte Artbeschreibung aufgebaut? Ist der Mensch eine Tierart, und wo im Stammbaum der Tiere ist er dann anzusiedeln?
Warum sind ein Wald, ein Teich oder eine Wiese Orte für interessante Entdeckungen, und zwar insbesondere auch für Kinder? Was lebt denn da, und wie ist es an seinen Lebensraum angepasst? Was haben unterschiedliche Arten in solchen Lebensräumen eigentlich miteinander zu tun? Und wie beobachtet man Tierverhalten am besten? Wie dokumentiert man es aussagekräftig, um sein Wissen später mit Freunden oder über soziale Netzwerke teilen zu können?
Wie kommt es zum sogenannten Global Warming, der globalen Klimaerwärmung? Wie können wir sie nachweisen? Warum ist sie zu einem beträchtlichen Teil menschengemacht? Und welche Auswirkungen haben Klimaerwärmung und die Ausbeutung natürlicher Ressourcen (Energiespeicher, Rohstoffe, wie zum Beispiel Tropenholz) für die Zukunft der Menschheit und die Artenvielfalt auf unserer Erde. Welche Auswege erhofft man sich? Woran wird derzeit gearbeitet?
Was benötigt man zur Naturfotografie, was, wenn man zusätzlich oder alternativ auch noch auf gutem Niveau filmen möchte? Was ist grundsätzlich wichtiger: Das Equipment oder das Bild, das zuvor im Kopf des Fotografen oder Filmers entsteht? Muss taugliches Equipment immer ultra-teuer sein? Welche Software eignet sich am besten zum Editieren? Was genügt dabei den Ansprüchen von Anfängern, was benötigen Fortgeschrittene und Profis? Wie filme oder fotografiere ich draußen in der Natur? Wie hole ich stattdessen die Natur in mein Fotostudio und inszeniere sie dort so, dass es aussieht, als habe man im Freien gearbeitet?
Dies sind alles mögliche Themen, die in meinem Unterricht, meinen Kursen oder Vorträgen vertieft werden können. Beliebige weitere Fragestellungen aus den Bereichen Naturkunde, Biologie, Ökologie und Evolution arbeite ich gerne für Sie aus.
I offer lessons, remedial courses, lectures and advanced training courses on the subjects of natural history, nature conservation, biodiversity, ecology, climate protection and evolution, as well as lessons or lectures on nature photography or nature filming. All this either on a fee basis or via employment. Please see my menu item on the subject of teaching for further information. Of course, I have proofs of qualifications for my various previous teaching activities as well as my professional competence. Please also note my menu item Curriculum Vitae.
But what are my topics? In the following you will find interesting questions from my areas of competence:
What is an ecosystem? Which ecosystems have been well studied and which not? How well do you know the biodiversity of micro habitats in Germany and what is known about their biological (ecological) relationships? What is actually a species, what are sibling species, and what is meant by a species complex (cryptic species group)? Is the extinction of species a normal part of evolution or is the extinction of a species always an alarming indicator of a (possibly human-made) natural disaster? How many species from all groups of organisms worldwide do we know, and roughly how many do we not yet know? Why do we still not know many species, even in Germany? How do we recognize new species and how is a so-called species description structured? Are humans an animal species, and if so, where do they belong in the animal tree?
Why are a forest, a pond or a meadow places for interesting discoveries, especially for children? What lives there and how is it adapted to its habitat? What do different species actually have to do with each other in such habitats? And what is the best way to observe animal behavior? How can you document it meaningfully so that you can later share your knowledge with friends or via social networks?
How does the global warming come about? How can we prove its existence? Why is it largely human-made? And what are the effects of global warming and the exploitation of natural resources (energy stores, raw materials such as tropical wood) on the future of humanity and biodiversity on our planet? What exits to avoid emergency situations are we hoping for? What are scientists currently working on to ensure a healthy human future?
What do we need for nature photography, what if we also want to film at a good level in addition or as an alternative? What is fundamentally more important: the equipment or the image that is created in the head of the photographer or filmmaker? Does suitable equipment always have to be ultra-expensive? Which software is best for editing? What meets the requirements of beginners, what do advanced and professionals need? How do we film or take photos outdoors in nature? Instead, how do we bring nature into our photo studio and stage it there in such a way that it looks as if we were working outdoors?
These are all possible topics that can be deepened in my teaching, courses or lectures. I would be happy to work out any other questions from the fields of natural history, biology, ecology and evolution for you.
all copyrights Stefan F. Wirth Berlin 2022
A collegue from the field of entomology recently wrote me his impressions about the situation of scientific fundings in the western world, as he travels around and stays with each of his feet in another country. He said that everybody knows about the importance of the biodiversity on earth and that consequently everybody agrees that research on the biodiversity deserves to be funded. But he continued that this does not mean that the same people would agree that biodiversity research requires experts and that experts would even need to be paid. Thus many of his former students in the US or Germany need to survive with temporary jobs other than their expertises would require.
But also an international unbalance of financial resources, available for fundamental research in entomology or for example acarology (my discipline) can lead to experts being sorted out, although they would be urgently needed. The focus, based on the considered eligibility of research, changed withing the last 25 years. As before Germany was a hotspot for high-quality research in the fields of evolutionary biology, systematics and biodiversity research, that focus of interest is now located in the USA. They invest more money into these sciences than all European countries together.
This can additionally have consequences for the quality of such kinds of research. It is no secret that the general educational level in the US is at least in some areas comparably low, many people don’t speak foreign languages, they often don’t travel abroad, and they live in midst of a mentality, which says „America first“. Biodiversity research would in the old German world of science regularly be connected with many „but consider that…“ conditions. The American way, in some cases, might want to have it easier. They might say: what’s the problem? What do they want to have? Yes, right, they want the numbers of all discovered species. They ask for numbers, thus we do our best to give them numbers, as fast as possible.
Some privileged US-researchers might even misuse their financial power to decide, who in other countries is and who is not. But I say in a rhetoric „you“: Use your fundings to involve as many suffering experts from abroad as possible, instead of center too much work and responsibility on yourself, you won’t have enough time due to too many species, which still need to be discovered and described. Don’t work too fast and don’t risk to become too superficial. Each species deserves time. Share the work with others and make science benefit from the different kinds of backgrounds in different areas of the world.
A mite of the Histiostomatidae, found in Amsterdam in its original substrate as example for the topic „Acarology“
All copyrights (also of SEM photo): Dr. rer. nat. Stefan F. Wirth, Berlin July 2020
We recently read a lot about the pandemic consequences of infections with the new corona virus Sars-CoV-2, most are medical issues, hygienic advises and information about political reactions in different countries worldwide. But there is not much known about the biological host reservoir, putative intermediate hosts and how the human infections might be explained. It is a normal lack of information, because the scientific research about topics, being generally new to science, is time costing, especially, when life strategies and the population dynamics of organisms a concerned. Organisms? Viruses are per definitionem not considered organisms, because they lack important aspects, which characterize real life: they cannot reproduce on their own power, they do not have an own metabolism, no ingestion, no excretion. But they are organic and show traces of life by possessing a genome, which might indicate that they evolved from living cells. Viruses represent a diverse group of protein bodies containing nucleic acid, either DNA or RNA.
New corona virus Sars-CoV-2, Wikipedia: CDC/ Alissa Eckert, MS; Dan Higgins, MAM / Public domain
Viruses in general, host specificity, host increase, host change
For reproduction viruses depend on living host cells, which they reprogram by inserting their virus genome into the cell’s genome in order to stimulate the forming of a number of virus copies, all that happening on cost of the host cell’s life. Thus viruses need to be named parasites as they harm their hosts to their own advantage. Different groups of viruses attack different kinds of cells using in detail different methods to enslave their host cells. There are plant viruses, viruses associated with bacteria (named bacteriophages) and animalistic viruses. They all show characters, which are typical for parasite – host – relationships. Parasitic partners of any kind of host – parasite – relationship can be exclusively associated with one host species only (host specificity) or a limited group of systematically closely related hosts, while others can have a wider range of different host species. The latter generally might have evolved out of the former, although also the opposite direction is thinkable. When former host-specific parasites make themselves one or even several further hosts accessible, then this phenomenon is named host-increase (Wirtserweiterung). In case an new host was infested as permanent host, while the former host is given up, then a so called host change (Wirtswechsel) happened. The same term is also used in a different context, namely when a parasite requires in its development a change between different hosts.
Host specificity: A parasite (or an organism with similar life-strategy) is associated with one host only, which requires a specialization and a competition between host evolution and parasite evolution (coevolution). This strategy needs to be separated from generalism, which means that a parasite has a very wide range of not related regular main hosts. Host specificity is more common than generalism. But this also depends on definitions. I herewith define the association with one main host species only as host specificity. But I furthermore consider host specificity also given, when parasite-host relations are specific on a higher taxonomic level, for example, when certain closely related genera of parasites are specialized for certain closely related genera of hosts. This part of my definition has variable borders. In the chapter after next, I describe the parasitic case of the trematode Leucochloridium paradoxum, whose main hosts are represented by different systematically not closer related bird species. A host specificy on the level of birds in general (Aves), then present in only some species with similar food preferences might already need to be named a limited generalism.
Obligatory host change in ticks and lifstyle-change in water mites
Some parasites need several hosts to be enabled to finish their life-cycles. This is another context, in which the German term „Wirtswechsel“ (host change) is used. In that kind of parasite – host – association, the host change is often obligatory, meaning that the parasite cannot survive in the absence of one of the required hosts. The castor bean tick Ixodes ricinus represents a parasite, which needs a host change to successfully go through its full development until adulthood, but there is a wider range of suitable hosts, as intermediate host and as final host. Thus the tick is a generalist with obligatory host change. Water mites (Hydrachnidia) are parasitic as first nymphs (juvenile instar, usually named „larva“) and predators as older nymphs and adults. A host specificity of „larvae“ can appear, but a wider range of host species is common. These mites perform a life style change during their development.
Intermediate host, for example in the parasitic flatworm Leucochloridium paradoxum
An example for a parasite, obligatory requiring a specific intermediate host, is the flatworm Leucochloridium paradoxum („green-banded broodsac“, Trematoda, Platyhelmintes), whose larvae (miracidium) need to infest snails of the genus Succinea. This trematode parasite is host specific for a genus of snails, while there is no specificity for their main hosts. They parasite birds, but infest different bird species, which are not closer related to each other, such as finches, the crow family Corvidae or woodpeckers. Although there is a main host specificity on the very high taxonomic level of Aves, the use of the term (limited) generalism might in this case even be appropriate. Inside the smail’s midgut gland, miracidia (larvae) modify into another larva-form, named cercaria, which invade the liver, where they form so called sporocysts, sac-shaped muscular tubes, which grow through the entire snail host until they reach the snail’s tentacles, which they fill up with their tube-shaped bodies entirely. Lastly the snail is unable to retract her swollen organs. The snail tentacles are now well visible as conspicuous greenish stripes, pulsating permanently. The sporocysts as larval stage of this trematode parasite do even more than only increasing the visibility of the snail for bird predators, which represent the worm’s final host. They additionally manipulate the nervous system of the snail so far that the snail performs an unusual behavior and moves towards very well exposed elevated areas, such as leaves of adjacent plants. Thus the probability to be eaten by birds is remarkably increased.
Host specificity on humans with side-hosts and coevolution with the ancestor line of Homo sapiens: skin mite Sarcoptes scabiei
An interesting example of a host specificity with numerous side-hosts and even an additional host-increase is the skin parasitic mite Sarcoptes scabiei (also named the „seven-year itch“). It was originally exclusively specific for Homo sapiens and accompanied mankind over its entire evolution (e. g. J. R. H. Andrew’s Acarologia, 1983). Systematical relatives of that mite species can only be found within the Great Apes. Originating from the recent Homo sapiens, S. scabiei conquered the human’s domestic animals, such as dogs or bovine animals within long-term periods, in which humans and their domestic animals had shared the same buildings or even rooms. Domestic animals may transfer the mite-parasite subsequently to wild animals. In case main host (humans) and side hosts (domestic animals, wild animals) can supply everything, which the parasite needs for its development without the necessity to leave its host specimen, one might speak about real hosts. In case side hosts cannot supply the necessary basic equipment, they represent either intermediate hosts or dead-end hosts. It can for example be discussed, whether dogs might in fact be dead-end hosts, as the skin disease can harm them under certain conditions to dead.
Host increase due to the globalisation and human economic interests: example honey bee parasite Varroa destructor (mite)
Another example of a former host specificity on a species‘ level with host increase is the mite Varroa destructor (Parasitiformes, Mesostigmata). It was originally specific for the Eastern honey bee Apis cerana. The mite could only switch over to the Western honey bee Apis mellifera due to a human influence: Men transferred A. mellifera for economic reasons to the natural habitats of A. cerana in Eastern Asia, were it got infected by the mite V. destructor. A subsequent transfer of the Western honeybee back home established the mite parasite in Western countries. As A. mellifera colonies are much more harmed by V. destructor than its original host, our honey bee must be considered as an intermediate case between a new host and a dead-end host. Human international traffic enabled this host-increase primarily, although there are areas between Afghanistan and Iraq, where both bee species coexist due to natural distribution. But there is an almost insurmountable (allopatric) desert border between the population of both species of about 360 to 600 kilometers, although there are evidences for bees rarely surmounting this border. Thus a natural mite transfer between closely related bee species might have happened additionally. Species of animals, plants, fungi or bacteria and even viruses, which successfully established new (additional) living spaces are named neobiota or alien species.
Mite Varroa destructor, Wikipedia: The original uploader was Tullius at German Wikipedia. / Public domain
Can viruses as non-living genome possessing lumps be subject of evolution and complex host – parasite relationships?
Can this high complexity of modes of parasite – host – relationships in living organisms also be found in virus – host – relationships, although viruses do not represent living organisms at all according to biological definitions? The answer is yes, because viruses do not only share a genome with living cells, but based on this genome even are subject to the mechanisms of evolution. And evolution was the most important factor in all the mentioned complex parasite – host – interactions.
Parasitism versus mutualism or harming the host or not harming the host
Two different life-strategies with similar mechanisms as organism – to – organism associations
Are there other organism – to – organism relationships, being subject to a similar complexity than found in parasites with their hosts? Yes, a superordinate term for other close associations between different organism species is mutualism. While parasites need to harm their hosts by using them as final living-sources, mutualists are considered to practice a more neutral host contact, which per theoretic definition means that nobody harms anybody. But the assumption of a neutrality is in fact an artificial construct, as in detail it can come out that some of these organism associations represent unrecognized parasite-relationships, while in other cases a benefit for both partners (symbiosis) or for one partner only might be discovered in future studies. At least so called mutualists share as a feature that harmfulness or benefit are not easily noticeable.
Phoresy: taking a ride on a taxi-host as example of mutualistic relationships
An example for a more neutral organism, at least not harming association is called phoresy. It is often performed by nematodes and mites. These tiny organisms take a ride on bigger animals in order to become carried from one habitat to another. This „taxi-association“ is considered being of advantage for the phoretic part and harmless for the carrier (in English also often named host). But there are seeming phoretic interactions known, which based on developing technical scientific standards could be identified as unusual cases of parasitism. An example is a phoretic instar of an astigmatid mite (Astigmata, Acariformes), which as all phoretic instars within this big mite clade has no functional mouth, but sucking structures to fix itself to its host. This specific mite species had evolved a mechanism for opening the host cuticle in order to incorporate blood of its host using these sucking organs. This is unlike the common use of homologous suckers in related mite taxa, where they (as far as known so far) only support the adherence.
Another interesting example of a phoretic mite is Histiostoma blomquisti (Histiostomatidae, Astigmata), which is specifically associated with the red imported fire ant (sometimes referred as RIFA) Solenopsis invicta, which worldwide appears as troublesome neozoon, again a result of human global traffic. I am the scientific describer of that mite, and my research about it’s biology and abundance in ant nests refers to populations in Louisiana (USA). An interesting aspect is that the ant is originally native to Southern America. We lack studies, whether the mite appears in the native habitats of the ant also as its specific cohabitant or whether it originally deals with a wider range of phoretic hosts. We do not even know, whether the mite is at all native to the same area, in which S. invicta had its natural distribution. On one hand, we hypothesise that, but there is also a theoretical option that the mite performed a subsequent host change in areas, for example in the Southern USA, where the ant was accidentally established via sandy ballast substrate of ships as neozoon. It is further more not known, whether the mite – ant – relationship is indeed neutral, at least with no noticeable harming features. I discovered (S. Wirth & J. C. Moser, Acarologia 2010) that mite deutonymphs (= phoretic instar) can attach to active nest queens in such extraordinary high numbers (hundreds of mite specimens) that mobility restrictions for the concerned queens were sometimes visible. On the other hand, my video documentations showed that even completely overcrowded queens could still freely move and, much more important: stayed reproductive. The purpose of the mites inside the fire ant nests is unknown. But generally, mites of the Histiostomatidae can appear as beneficial animals in ant nests. At least according to my findings about the mite Histiostoma bakeri, which is a phoretic associate of the leafcutter ant Atta texana in Southern USA. I discovered these mites improving the hygienic conditions inside specific nest chambers (detritus chambers) due to their fungi and bacteria feeding activities (Wirth & Moser, European Association of Acarologists proceedings, 2008).
I will in different chapters of this article repeatedly refer to examples with phoretic mites of the family Histiostomatidae (Astigmata, Acariformes). As mutualism and parasitism follow similar organism-host association patterns, I will in those chapters not each time mention again that examples with these mites do not concern parasitism, but mutualism. It is by the way no accident that both life-strategies share common features, as there are examples known, which indicate that one strategy can evolve out of the other.
Mite Histiostoma blomquisti Wirth & Moser, 2010 (Histiostomatidae, Astigmata, Acariformes) on queens of ant Solenopsis invicta, Pineville/ Louisiana, copyrights Stefan F. Wirth
Mutualism often used as neutral term for organism associations with unknown effect of both partners to each other.
The copepod (Crustacea) Ommatokoita elongata on Greenland and sleeper sharks
So called mutualistic associations can sometimes represent interactions of unknown benefits or damage regarding both of the associated partners. Another interesting example of such an association with a not yet understood status is the copepod Ommatokoita elongata (Crustacea), which was discovered as specific cohabitant on the Greenland shark (Somniosus microcephalus) and the pacific sleeper shark (Somniosus pacificus). Larvae of the crustacean in their copepodit stadium and adult females attach to the ocular globes of the shark, where they can cause visible tissue damages. They are thus considered being parasites, although alternating hypotheses assume a more neutral mutualistic copepod – shark – association, based on the sometimes high abundance of the crustacean on one shark specimen (B. Berland, Nature, 1961). There are even assumptions about a benefit contributed by the copepode to the sharks: reasearchers say that it might improve the shark’s hunting success by attracting suitable prey with bioluminescence signals.
Shark Somniosus pacificus, Wikipedia: National Oceanic and Atmospheric Administration / Public domain
Greenland shark with copepod Ommatokoita elongata, hardly visible, when the shark turns to show his right eye, Youtube: copyrights The Canadian Press, video by Ben Singer, footage Brynn Devine, Marine institute of Memorial University of Newfoundland
Human parasites with mutualistic features: the mites Demodex folliculorum and D. brevis
Can viruses be compared with some mites, nematodes or copepodes by performing mutualistic virus – host – relationships? A priori it must be stated that they are unable for a neutral relationship with another organism, as they need the destruction of living cells for their own persistence. But indeed there are viruses known, causing no known diseases and thus being named passenger viruses. But first, an example of an organismic example of parasitism without harmfulness will be presented: the mites Demodex folliculorum and Demodex brevis (Trombidiformes, Prostigmata), which appear as so named „face mites“ inside hair follicles of humans, preferring eyebrows and eyelashes, but also other hairy body parts. The abundance in humans is high and grows with a human age. According to Schaller, M. (2004), new born children are free of Demodex, while over 70 years old people are at almost 100 percent infested with the mites. The mite in fact is a parasite and feeds on sebum from the sebaceous glands. Incorporating needed human gland secretions must be named parasitism. Nevertheless mites under normal conditions cause no visible damages nor do they seem to harm their host noticeably.
So called passenger viruses as mutualists with a more or less neutral affect to their human hosts
Such a parasitic relationship might be comparable with so called passenger viruses, which do not harm noticeably, although they destroy living tissue as all viruses do. They can accompany more harmful viruses and even might harm the pathological success of the diseases, caused by these harmful viruses, and for example might slow the disease’s progression. An example is the GB virus C (GBV-C), which was before known as Hepatitis G virus. The virus is common in humans and shows no pathogenic damaging effect. According to an US-study, about 13 percent of probands, whose blood was examined, possessed antibodies against the virus. GBV-C is considered to slow the effects of an HIV disease by negatively effecting the replication of the HI-virus.
Host increase towards systematically not closer related new hosts
Example for a transfer within related host taxa in mites is the bark-beetle-clade within Histiostomatidae (Astigmata), an example for non related side hosts is the mite Histiostoma maritimum (Histiostomatidae, Astigmata)
Do side-hosts or intermediate hosts as results of host increases commonly need to be systematically close relatives of the main host? The answer is no, although parasites are usually better pre-adapted in infesting a host, which shares a maximum of common characters with the main host. Within the mite family Histiostomatidae, there exists a clade of mites being associated with a clade of beetles. I named it bark beetle-clade (e.g. Wirth, phd thesis, 2004). Mites and bark beetles performed a parallel evolution, which required host increases and host changes towards related hosts and subsequent evolutionary adaptations to harmonize with these new hosts, either to become specific for a new host or to deal with a range of host species.
But the transfer of a parasite to new hosts can also happen towards not closely related host species, representing a scenery being based on a common ecological context between main hosts and side hosts. The phoretic mite Histiostoma maritimum for example is host specific for at least two closely related beetle-species of genus Heterocerus (Heteroceridae). But the mite regularly also appears on predatory beetles of genera Elaphrus and Bembidion (Elaphrus cupreus and Bembidion dentellum, Carabidae) (S. Wirth, phd thesis 2004 and subsequent studies). These beetles partly share the same habitats with Heterocerus: sapropel around ponds, being exposed to sunlight and warmth. In my research about the mite H. maritimum, I hypothesised that the phoretic mite instar might switch over to Elaphrus and Bembidion, for example when these predators feed on adult Heterocerus beetles, larvae or cadavers. Although I could regularly find mites in lower abundances over years on the side hosts (collected in the Heterocerus sampling sites), it is unknown, whether the „switch-over“-scenario was a starting event in an evolutionary past to establish the mite to new additional hosts, where they would today survive more or less independently from the original Heterocerus source, or whether the mites regularly need to switch over in the above mentioned situations, and in consequence side hosts with no Heterocerus-contact would thus lack the mite. A possible support for the latter hypothesis are my laboratory findings about the preferred developmental habitat of the mite, which was cadavers of died Heterocerus beetles. In my experiments the mite remained on its Heterocerus– carrier until this died. Mites subsequently developed on the beetle’s cadavers, feeding there on bacteria and fungi (the phenomenon is named necromeny). Mites under laboratory conditions developed also seemingly successfully on E. cupreus– and B.dentellum-cadavers. But I could so far never continue these studies and don’t know, whether or how well mite colonies with having only cadavers of these two side-hosts available would reproduce compared to mites being reared in Heterocerus settings. In case of a strict substrate specialization for Heterocerus cadavers, the side hosts would be dead-end hosts, and permanent reinfections from the original host source would be required to explain the regular mite abundance in Elaphrus and Bembidion.
Histiostoma maritimum, a adult female with conspicuous copulation opening, b both adult genders in dorsal view, c, d copulation opening in dorsal and sideview, SEM, Berlin 2020/ ca. 2002, copyrights Stefan F. Wirth
Assumed transfer of virus SARS-CoV-2 from bat main hosts via a pangolin as intermediate host towards humans:
There is an ecological context between bats and pangolins
The new corona virus SARS-CoV-2 is assumed to be host specific to a group of animals and from there infesting another animal as intermediatehost, from which presumably humans were opened up as new host source. There are researchers interpreting us humans as an dead-end hosts, as unlike in bats human people can be harmed remarkably with the lung disease COVID-19 (corona virus disease 2019), triggered by SARS-CoV-2. As at least from a general statistical point of view a high majority of infested people shows no or only slight symptoms, thus it can up-to-date not be excluded that Homo sapiens is in order to become a fully potential side host, because all a parasite needs in order to „survive“ before all other requirements is the (statistically) surviving of its host.
There is evidence that bats (Chiroptera) represent the main host, thus representing the „natural virus reservoir“, while pangolins (Pholidota) presumably act as intermediate hosts. This main-host-to-intermediate host context is for example reported as putative scenario by Ye Z.-W et al. (Int Biol Sci, 2020), who stated that based on molecular features the bat Rhinolophus affinis (Rhinolophidae, Chiroptera) is hosting a virus most similar to SARS-CoV-2 differing from all other known corona viruses (Similarity 96.2 %, nucleotide homology). The pangolin species Manis javanica was identified to carry formerly unknown CoV genomes, being according to the same authors with 85-92 % similar to SARS-CoV-2 (nucleotide sequence homology).
Bat Rhinolophus affinis as known reservoir of a virus most similar to Sars-CoV-2. Wiki commons: Naturalis Biodiversity Center
Pangolins and Chiroptera (bats and megabats, this taxon subsequently sometimes refereed as „bats“) are systematically not closer related to each other. Pangolins (Pholidota) are considered to represent the sister taxon of the clade Carnivora. Chiroptera were reconstructed as sister taxon to the clade Euungulata (containing animals such as horses, cattle or whales). But both, Chiroptera and Pholidota, can be connected by an ecological context. Pangolins (Pholidota) are species, which are either adapted to live preferably on the ground, or to spent most of their time on trees. Both types are specialised ant and termite feeders, which use cavities on the ground or inside trees as hideaways. They additionally give birth to their offspring inside these burrows and subsequently use to stay there with their young for a while. Such cavities can accidentally be the same time aggregation and resting places for bats, excluding megabats, which use to rest during daytime on exposed areas on trees. Manis javanica has a semi-arboricol life-style, spending time in trees and on the ground. This pangolin uses different resting cavities, either subterranean burrows or tree cavities.
Chinese pangolin Manis pentadactyla, a ground living species, Wikipedia: nachbarnebenan / Public domain, Zoo Leipzig, Tou Feng
Pangolin Manis javanica as known host of a virus similar to virus SARS -CoV-2. Wikipedia: creative commons Piekfrosch / CC BY-SA
Chiroptera and Pangolins are in South Eastern counties often subject to hunting, as both for example play a role in the traditional Chinese medicine. Thus a virus transfer to humans via main host or via the putative intermediate host is assumed to have happened on animal markets (in the province Wuhan in China).
Which indications point to animal hosts as original source of virus SARS -CoV-2 ?
The scientists Andersen et. al (2020) explain there was no virus-engineering instead of a natural evolution
But which proofs exist that animal hosts sources such as Chiroptera and pangolins are involved in the transfer of the virus SARS -CoV-2 to humans? The lack of general knowledge is still fundament for conspiracy theories, such as an artificial creation of the new corona virus in laboratories with biological warfare purposes.
K.G. Andersen et al. („The proximal origin of SARS-CoV-2“, Nature Medicine, 2020) concluded based on their molecular research that the genetic template for specific spike proteins forming structures, which the virus body possesses on its outside for holding on and penetrating into the host cells, showed evidence for a natural evolution and not for an engineering. They argue with the strong efficiency of the spikes at binding human cells, which makes an engineering implausible and evolution based on natural selection highly probable. The authors additionally examined the overall molecular structure of the backbone of SARS-CoV-2. Backbone can be explained as the „skeleton spine“ of a macromolecule as a continuous row of covalent bond atoms. This overall backbone structure of the new corona virus is according to the authors similar to viruses, which were isolated from Chiroptera and pangolins and dissimilar to other corona viruses, which are already known to science.
Spikes (here in red) in Sars-CoV-2 hold on and penetrate into host cells, Wikipedia: CDC/ Alissa Eckert, MS; Dan Higgins, MAM / Public domain
Can a host increase happen more or less spontaneously with a subsequent enormous success (as for example in virus SARS-CoV-2)?
And: Can the complexity of adaptations to a main host decide for the option of a host increase?
An example for a tendency to spontaneous temporary host changes is mite Histiostoma piceae (Histiostomatidae, Astigmata)
Is it imaginable that a host change or a host increase happens spontaneously and subsequently having such a remarkable impact to the new host, as it is recently ongoing with the SARS-CoV-2 pandemic? Host specificity, host changes and parasitism or mutualism in general are result of evolution. The most common case of evolutionary changes in organisms or viruses is a slow process of stepwise modifications being based on mutations and natural selection.
But it needs also to be stated that as more complex the pattern of characters is (genome, morphology, behavior, function-morphology, reproduction biology etc.), which binds a parasite or mutualist to a specific host, as more evolutionary steps are necessary to perform a host change and as longer an exposure to mutation and selection would need to take place. However it is alternatively possible that a host specificity is only based on a few, but important features. Slighter ecological pressures focusing towards these features might then theoretically allow rather fast host changes.
As an example with a putatively reduced complexity of host adaptations I herewith introduce the phoretic mite Histiostoms piceae (Astigmata, Histiostomatidae), which I repeatedly studied and reared under laboratory conditions. The scientific describer of this species (Scheucher, 1957) discovered a strict host specificity to the bark beetle Ips typographus. According to my and her research, the mite has along the geographic distribution of that bark beetle a high abundance, beetles without the mite are rare. In 2016 I discovered H. piceae being additionally associated with Ips cembrae as a second regular host. I cembrae represents the sibling species of I. typographus (Wirth, Weis, Pernek, Sumarski List, 2016). Exceptions are smaller bark beetle species, which regularly burrow their galleries into those of I. typographus or I. cembrae. It is unknown, whether these small bark beetles as cohabitants of I. typographus carry the mite temporarily or regularly. But the former might be confirmed by the following interesting phenomenon in the mite H. piceae:
In case of very high numbers of mites inside bark beetle galleries and a relatively low numbers of corresponding Ips species, the phoretic instar of the mite attaches under natural field conditions all available arthropods inside or adjacent to the galleries of the main hosts, including bigger mite species, different beetle species or – as already mentioned – smaller bark beetle species (for example my studies in the area of the city Tyumen, Siberia, Russia, 2015-2016). This indiscriminateness for specific hosts under certain conditions might indicate that the substrate specificity of the mite H. piceae is more developed than the phoretic specificity for the host insect itself as a carrier . In such a case, I would generally expect that a host change or a host increase might faster happen in future evolutionary steps than in mite species, which are strictly choosy for their specific host carrier. In H. piceae the tolerance for a variety of carriers (unlike the specificity for substrate conditions) might in a future evolution even succeed as pre-adaptation, which under suitable circumstances might spontaneously allow a regular transfer to new hosts. A second important step towards a real host increase would require that the mite becomes able to stay permanently on its new host. In the H. piceae context the evolution of a tolerance for different substrate conditions might once become an important selective factor in may be opening up new permanent host-associations.
Temporary side hosts, as described in the above explained observations, would represent nothing then dead-end hosts, as they are unable to carry the phoretic mite to suitable habitats for its development. But under favorable circumstances, a former dead-end host might even become a new permanent host.
Histiostoma piceae, a adult female in side view, b in dorsal view, c mouthparts and digitis fixus, d adult male in dorsal view, e in ventral view, Berlin 2020/ ca. 2002, copyrights Stefan F. Wirth
Phoretic instar of Histiostoma piceae, ventral view, lightmicroscope with dig contrast, Tyumen (Siberia, Russia), 2016, copyrights Stefan F. Wirth
Two possible ways of virus transfer from bats to humans according to Andersen et al. (Nature Medicine, 2020)
Did the virus evolution towards the recent state happened prior to a first human infection, namely inside animal main host populations, or did it happen afterwards inside human populations?
As there is not yet much known about the presumed host specificity of the virus SARS-CoV-2, Andersen et al. (Nature Medicine, 2020) reconstructed based on their up-to-date knowledge two possible ways of a virus transfer from bats to humans and finally to the recent pandemic situation in the world:
The virus might have evolved its recent human-pathogenic features within the main host populations of bats. Natural selection must have been the corresponding major driving force. The relevant adaptations are represented by the above mentioned two molecular characters of the spike proteins in SARS-CoV-2 (receptor-binding domain for host cell binding and cleavage sites for an opening up of the virus). Under such circumstances the authors expect that the infection of humans could have happened with an immediate effect, leading at once into the pandemic situation of today. An intermediate host would in this option be not obligatory. A direct transfer from bats to humans might be imaginable.
The second option is based on findings that corona viruses in pangolins possess similar receptor-binding domains (RBD) as in the human SARS-CoV-2 version. Thus the authors reconstruct a version according to which a non or less pathogenic form of the new corona virus was via pangolins transferred to humans and circulated there for an unknown period of time. Even further possible intermediate hosts, such as ferrets or civets, are considered to have been involved in that scenario. During its time inside human populations the virus would have developed its recent features due to evolution and finally was able to be spread explosively between human populations on a pandemic level.
A higher probability for one of the two scenarios can according to the up-to-date knowledge not be assumed
I am not sure, whether the authors take under consideration with their second option that pangolins might even represent a main host and whether bats would not necessarily be involved in the animal-human transfer of the virus. But according to Ye Z.-W. et al. (Int Biol Sci, 2020) the context between bats, pangolins and humans was stated: „We cannot exclude the possibility that pangolin is one of the intermediate animal hosts of SARS-CoV-2“. But whether the pangolin is intermediate host or main host would at this point not effect the general conclusion of each of the two scenarios. The virus was either pre-adapted regarding efficient spike protein characters and then infested human populations rapidly or was transferred to humans via an animal host and subsequently evolved its key-features for a pandemic „success“ within human populations. Although the authors have up-to-date no indications allowing a preference for one of the scenarios, they point out that the potential of new SARS-CoV-2 outbreaks after the extinction of the recent human pandemic would be much higher in case of the scenario one, as the pathogenic virus would under these conditions survive in the animal main host populations.
I would as addition to scenario two suggest to test a modified hypothetic scenario, in which the non pathogenic ancestral version of the virus did not only circulate between human populations until it reached its pandemic key-features, but even circulated between humans and animal hosts forth and back for a longer time. This would according to my understanding of evolution improve the probability of a stepwise evolution of important key-features.
Special and unusual features of main hosts can improve the diversity within their parasites, important conditions for subsequent host changes: a very efficient immune system in bats pushes the evolution of their viruses
Chiroptera (bats and megabats) are not only known as putative main hosts for SARS-CoV-2, but also for Mers, Sars, Marburg and ebola viruses. Scientists did a research about the question, whether there are specific features existing, which explain, why Chiroptera are favorable hosts for viruses with a seemingly potential for epidemic and pandemic effects in human populations.
C. E. Brook et al. (eLife, 2020) discovered an unusual efficient immune system in Chiroptera, which they think protects these hosts from harmful diseases by their virus parasites. This bat immune system is considered being the evolutionary driving force for the variety of viruses and their relatively fast modifications, as they would need to compete with immune system responses by regularly evolving new adaptive features.
The authors discovered that the antiviral messenger substance interferone-alpha is released in most mammals as a response to the detection of viral genetic material inside body cells. Whereas they found Chiroptera releasing this messenger substance permanently. This would according to the scientists enhance the virus defense in bats and might explain that the above named viruses do not trigger noticeable diseases in their main host recervoir.
I would resume that such conditions might support the scenario one of Andersen et al. (Nature Medicine, 2020), according to which viral key features to infest humans had evolved prior inside the animal host populations. Regular new virus modifications as result of the competition between these viruses and their bat-host immune responses might support the randomness of the development of features, which as pre-adaptations could support a relatively fast host change. Even when I generally prefer scenarios of stepwise adaptations of organisms to new conditions, a higher probability of the availability of suitable pre-adaptations might at least accelerate evolutionary proceedings.
Longtime parasite – host – relationships, a dead-end for the parasite?
Are relationships between organisms over longer time periods of advantage or disadvantage for parasitic or mutualistic passengers? A longtime host specificity of a parasite (or mutualist) requires a strict specialisation, which means complex morphological, ecological and behavioral adaptations.
According to the acarologists P. B. Klimov & B. Oconnor (Systematic Biology, 2013) long-term specialisations could impede the flexibility of such organisms to react to environmental changes via evolutionary adjustments. Thus parasites with long-term relationships to the same hosts might be endangered to reach a dead-end. They would die out. A possible way out from such a disastrous end can be a re-evolution of the parasite back to its ancestral free living conditions, a situation prior to the evolution of its parasitic host specificity. But Dollo’s law states that a complex trait cannot re-evolve again. Thus long-term parasitism could according to the law not other than leading into a dead end. Nevertheless the authors could present an impressive example as proof to the contrary: based on their complex research about house dust mites, the acarologists reconstructed that these mites were originally parasites of warm blooded animals and subsequently evolved into free living associates of mammals, as which they are of medical relevance due to the remarkable allergic reactions in humans.
I think that the access of this paper does contain enough general biological aspects to ask, whether the dead-end scenario of long-term parasite relationships might also concern viruses, which don’t have an option for a free living existence, as they don’t live at all and are unable to perform independent strategies. At least might this long-term scenario support the findings of C. E. Brook et al. (eLife, 2020) that only unusual and regularly changing features of a long-term host might trigger regular corresponding responses by the parasite, another option to prevent a parasite from a dead-end due to a long-term host relation. This might explain, why certain viruses often parasite bats and successfully persist there, while other suitable hosts lack the very efficient immune system of bats and thus cannot host a specialized virus permanently. Regarding SARS-CoV-2 such theories might indicate that the virus would finally move towards dead-ends in humans and other host species, but might permanently survive in chiropterans. It’s a statement only being worth of consideration, in case of scenario one of Andersen et al. (Nature Medicine, 2020). And only in case, it would come out that the virus adapts well to humans, which would require a much reduced harmfulness, as parasites cannot survive by killing their hosts. In case of a dead-end host due to high mortality rates instead of a normal host increase, aspects of a long-term relationship with such a host don’t need to be discussed, as a shorter temporary outbreak and no beginning of a long-term relationship at all would result out of it. One needs additionally to consider that viruses as non living organic bodies with genome and with an unusual ability for fast modifications might often not fit into biological models based on living organisms.
House dust mite Dermatophagoides pteronyssinus. Wikipedia creative commons: Gilles San Martin from Namur, Belgium / CC BY-SA
Host specificity must be differed from generalism. Known host-parasite specializations include a complexity of strategies. And even different kinds of hosts must be named, such as main host, side-host, intermediate host or dead-end host. Evolutionary steps such as host increase, host change or temporary hosts can appear. Parasitism and mutualism differ from each other as life-strategies, but share common features as association between different organisms: host specificity follows similar rules, an indication that both life-modes can evolve out of each other. The human globalization sometimes supports the spreading of parasites or their hosts over the world, host changes or host increases can thus be performed including organisms, which would under normal conditions get no contact to each other.
Viruses do not represent living organisms, but protein lumps with a genome and depend on living host cells for their reproduction and „survival“. like in living organisms, also viruses underlay the mechanisms of natural selection and evolution. Viral parasite – host – relationships show general similarities with features in living organisms, including options for a host change or host increase, the use of intermediate hosts or a kind of mutualism (passenger viruses). There is evidence that the main host reservoir of SARS-CoV-2 are Chiroptera, while pangolins (and other mammals) might represent intermediate hosts. Humans are either dead-end hosts (preferred by most authors) or result of a successful host increase. Researchers could not yet decide, whether features to infest humans in a pandemic context evolved prior to the transfer to humans inside animal main host populations or whether a harmless version changed to humans and in their populations evolved its pandemic potential. A major drive motor for a long-term successful relationship with bats is the unusual immune system in chiropterans.
Copyrights Dr. Stefan F. Wirth (phd), all rights reserved, excluding photos labeled as creative common content from Wikipedia sources. Berlin, 2 April 2020
J. R. H. Andrew’s (1983): the origin and evolution of host associations of Sarcoptes scabiei and the subfamily Sarcoptinae Murray. Acarologia XXIV, fasc. 1.
B. Berland (1961): Copepod Ommatokoita elongata (Grant) in the eyes of the Greenland Shark – a possible cause of mutual dependence. In: Nature, 191, S. 829–830. Cara E. Brook, M. Boots, K. Chandran, A. P. Dobson, C. Drosten, A. L. Graham, B. T. Grenfell, M. A. Müller, M. Ng, L-F. Wang, A. v. Leeuwen (2020): Accelerated viral dynamics in bat cell lines, with implications for zoonotic ermergence,eLife; 9:e48401.g W
Pavel B. Klimov, Barry OConnor, Is Permanent Parasitism Reversible? (2013): —Critical Evidence from Early Evolution of House Dust Mites, Systematic Biology, Volume 62, Issue 3, Pages 411–423.
Kristian G. Andersen, Andrew Rambaut, W. Ian Lipkin, Edward C. Holmes, Robert F. Garry (2020): The proximal origin of SARS-CoV-2. Nature Medicine. Martin Schaller: Demodex-Follikulitis. In: Gerd Plewig, Peter Kaudewitz, Christian A. Sander (Hrsg.): Fortschritte der praktischen Dermatologie und Venerologie 2004. Vorträge und Dia-Klinik der 19. Fortbildungswoche 2004. Fortbildungswoche für Praktische Dermatologie und Venerologie e.V. c/o Klinik und Poliklinik für Dermatologie und Allergologie LMU München in Verbindung mit dem Berufsverband der Deutschen Dermatologen e.V. (= Fortschritte der praktischen Dermatologie und Venerologie. 19). Springer Berlin, Berlin 2005, ISBN 3-540-21055-5, S. 273–276.
Wirth S. (2004): Phylogeny, biology and character transformations of the Histiostomatidae (Acari, Astigmata). phd thesis. Internet Publikation FU Berlin, http://www.diss.fu-berlin.de/2004/312.
Wirth, S. & Moser, J.C. (2008): Interactions of histiostomatid mites (Astigmata) and leafcutting ants. In: M. Bertrand, S. Kreiter, K.D. McCoy, A. Migeon, M. Navajas, M.-S. Tixier, L. Vial (Eds.), Integrative Acarology. Proceedings of the 6th Congress of the European Association of Acarologists: 378-384; EURAAC 2008, Montpellier, France.
Wirth S. & Moser J. C. (2010): Histiostoma blomquisti N. SP. (Acari: Histiostomatidae) A phoretic mite of the Red Imported Fire Ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Acarologia 50(3): 357-371.
Ye ZW, Yuan S, Yuen KS, Fung SY, Chan CP, Jin DY (2020): Zoonotic origins of human coronaviruses. Int J Biol Sci ; 16(10):1686-1697. doi:10.7150/ijbs.45472.
Zhang W., Chaloner K, Tillmann HL, Williams CF, Stapleton JT (2006): „Effect of Early and Late GB Virus C Viraemia on Survival of HIV-infected Individuals: A Meta-analysis“. HIV Med. 7 (3): 173–180.
It’s a new approach to photography for a photohrapher, when using a drone. Before starting for the flight, the photographer should at least have an idea about the possible perspectives, from which his copter shall capture the photos. This requires the ability of a three dimensional imagination. Unlike in the regular photography, the drone pilot does not see the scenery with his own eyes. Only a stepwise experience allows him to guess, how a forest and meadow landscape might look in a bird perspective at a level of 50 or even 100 m.
But despite of all three dimensional imagination abilities and experiences, much photography or videography is based on spontaneous shooting reactions, based on the transmitted live picture.
Edited landscape Drone photography, Berlin 2020, copyrights Stefan F. Wirth
If full automatic camera modi shall be avoided, manual presettings can already be made before starting the flight according to the general light conditions, finer adjustments can then follow in each specific case, when the drone is in the air.
An aerial photographer needs to resist to the danger of perceiving the environment in top-down view after some time with the drone camera only. The German laws define that a drone is only allowed to be flown in a distance of a direct visual contact. One reason is that one otherwise losses the feeling for a safe controllable space limit.
Before drones as flying cameras became commercially available for everybody, aerial photos or videos needed to be captured under more risky and also more costly conditions. Smaller planes, manned helicopters or cameras on balloons needed to take over the same function.
Being able to fly like a bird under remote control conditions is freedom for the spirit and at the same time freedom for an incredible creative flexibility.
All aspects of our world deserve being considered as drone photography motifs (respecting laws of course) . Whether a settling, a city, a street construction, people, architecture or nature sceneries, the drone technology enables new options and aesthetic experiences. I made experiences in different photo object types (the respectation of laws has always a priority). But for my own projects I prefer landscape, weather, season and art photography.
Drone photography mostly in Northern Berlin and adjacent regions in Brandenburg, copyrights Stefan F. Wirth
Flying in more or less remote areas with natural landscapes reduces the probability that a drone accident might harm people or architecture. But it is of course additionally important to bring no animals or plants in danger.
Landscape photos are the more interesting the more complex their composition is. But a forest with adjacent meadows is per se no guarantor for an impressive photographic piece of art.
Drone photography mostly in Northern Berlin and adjacent regions in Brandenburg, copyrights Stefan F. Wirth
Only the contrasts of colors, shapes and different landscape elements can under optimal conditions create complexity and a fulfilling picture composition. More or less sharp edges between for example forest areas and adjacent meadows might built up an impressive and even seemingly abstract pattern, making the shot to a fascinating piece of art.
Drone photography mostly in Northern Berlin and adjacent regions in Brandenburg, copyrights Stefan F. Wirth
City structures, such as architecture, streets or walkways, seem not to underlay bigger seasonal changes (in times withoug snow or rain) . Is that true? It of course is not, the seasonal different light conditions always cause different photographic or videovraphic looks of the same location. The lack of intense green or colorful vegetation spots in between creates additionally sceneries with very different moods.
Of course the effect of different seasons is especially distinct in the nature photography. Even in case that black and white photos would be preferred, leafless trees of a winter forest usually look remarkably more interesting than an amorphic mass of grey leaves. In the colored drone photography, nobody would doubt that the diversity of autumn colors allows a much more impressive composition of structures, shapes and lights.
But also in summer or spring, when only slightly differing green nuances dominate the sceneries, eye catching drone photography can be performed.
Drone photography mostly in Northern Berlin and adjacent regions in Brandenburg, copyrights Stefan F. Wirth
In case the greenish landscape sculpture itself does not allow a photographic highlight, then a dynamic sky can prevent the whole photo from getting lost in a boring piece of sadness.
One needs to keep in mind that a positioning of the drone camera with being for a longer time straightly directed into the sun might harm the camera sensor. Against the light photography can look stirring, but it’s often of advantage to avoid the sun body itself completely. Against the light photos usually lead to dark landscape elements in the foreground, almost consisting of silhouettes only. To receive more details on the photo it is recommended to record a higher amount of information. Raw files can be the best choice in this context, as they allow to develop details during editing, which were not visible before.
Drone photography mostly in Northern Berlin and adjacent regions in Brandenburg, copyrights Stefan F. Wirth
To become able for an improving editing of a photo, a minimum resolution of details should be available. A resolution of 20 megapixles or more offers enough buffer for art filters or manual changes of light, color, contrast etc. The Mavic 2 Zoom for example unlike its sibling brother Mavic 2 pro with a high quality 20 megapixles camera, offers different panorama modes. One of them is created as composition of several 12 megapixle photos, which the camera automatically puts together to a 45 megapixle piece. In case drone cameras allow a raw mode and additionally a high resolution, both of these options should be chosen.
Drone photography mostly in Northern Berlin and adjacent regions in Brandenburg, copyrights Stefan F. Wirth
Editing can have different functions combined with different intentions of the photographer. An almost perfect photo sometimes needs being only slightly digitally improved. Alternatively the entire photo might need to be stronger modified for aestethic and creative reasons to create the planned piece of art. The creativity of the photographer and editor at this has no limits, but it should be tried to avoid the ‚killing‘ of too much picture information.
Not every editing tool has a modern high quality level. Lightroom, Photoshop, pixlr and similar software of other developers must be recommended.
Drone pilot and service offering
I have more than three years of experience in the fields of drone photography and drone videography. I herewith offer my videographic dronepilot service for documentary projects, smaller movie projects, such as film – students- projects, image movie purposes or the videographic documentation of important private events, such as marriages.
I additionally offer my drone photography abilities for all kinds of fields and purposes. Preferably in and around Berlin. Please contact me via Instagram or Facebook ‚Stefan F. Wirth‘. I fly a Mavic 2 Zoom. Flying license (Kenntnisnachweis) and insurance for commercial Drone flights existant.
Ich biete mich als freiberuflicher Dienstleister der Drohnen- Videographie und Drohnen-Fotografie in allen Bereichen wie Dokumentarfilmproduktionen, kleineren Spielfilmproduktionen, zum Beispiel Studenten-Filmprjekten, Image-Filmen und Ähnlichem an. Kontaktaufnahme bitte via Facebook oder Instagram unter ‚Stefan F. Wirth‘. Ich fliege eine Mavic 2 Zoom. Kenntnisnachweis und Haftpflichtversicherung zur kommerziellen Nutzung vorhanden.
Some photo examples in higher resolution. Copyrights Stefan F. Wirth
The metropolis Berlin is the capital of Germany and much more than that. It represents an unusual green city. When using elevated viewpoints to watch the cityshape, then at least in summer visitors of Berlin can receive the impression of being in the midst of a greening huge landscapes with several villages in between.
Indeed related to other metropolitan cities of the world, Berlin is still partly not very densely populated and covered by remarkable huge natural countryside instead. The area of landing and runway strips of the former airport Tempelhof for example up to date represents the largest coherent green area inside a city worldwide. The so called Tempelhofer Feld was after the termination of the air traffic exposed to renaturation and is currently a very popular recreational park. It’s located in the South of the city.
Also the West and South-West partly represent nature reserve areas and are covered by the big urban forest Grunewald.
Meadows and wetlands in the North of Berlin as nature refuges
I am since two years discovering the Northern parts of Berlin, which according to my random observations (in comparison with other Berlin areas, such as Tempehofer Feld, Teufelsberg (Grunewald) and some urban parks in the center of the city; examples of species will be visible on my corresponding blog article) bears the greatest biodiversity in bloom visiting insects.
This is seemingly due to the complexity of different meadow-, field-, wetland- and bog-habitats, being originally shaped by the Weichselian-glaciers. I regularly visited the stream valley of the so called Tegeler Fließ with the lake Köppchensee. It’s a hilly area with different gradients of sunny slopes with partly Mediterranean climatic conditions, surrounded by different kinds of wetlands. This area is well known for its great biodiversity.
Between the villages Rosenthal, Lübars and Blankenfelde
But my drone flights present vast tracts in the South of that stream valley, consisting of fields, green meadows and wetlands. It is the area between the Berlin villages Rosenthal, Lübars and Blankenfelde. Inner urban agriculture is rare in metropolian cities worldwide, in Berlin there is only a small agriculture area in the South (Dahlem Dorf) and the fields between the named villages in the North.
Drone flights and bloom visiting insects
Fields and meadows with adjacent forests and wetlands in the North of Berlin, September 2019, copyrights Stefan F. Wirth. Please give my video also your like on Youtube.
Most part of the footage in my film represents the fields adjacent to the village Rosenthal. I newly discovered the partly quite tiny meadows between and adjacent to agricultural fields around Rosenthal this summer and discovered an impressive and steadily visible diversity of bloom visiting insects there. Fields as monoculture habitats usually bear a smaller biodiversity related to wild-growing nature zones. But due to the connection of the edges of fields with complex nature refuge zones around, I could observe a quite great number of species on closely adjacent meadows and even the natural border zones of these agricultural areas.
The footage was captured in 4K and D-cinelike quality using a Mavic 2 Zoom drone between September and October 2019.
Berlin, September/ October 2019, copyrights Stefan F. Wirth
Mites represent arachnids, which means that they share characters with much bigger organisms, such as spiders, skorpions or harvestmen. Their bodies consist of specialized bundles of segments, named tagmata. Two major tagmata are differed from each other in arachnids: prosoma, including legs and mouthparts, and opisthosoma, including for example the digestive and the reproductive systems.
Discussed diphyletic origin of mites
Mites are according to some acarological scientists eventually not longer just mites. The former two clades of mites, Parasitiformes and Acariformes, originally considered as sister taxa, were in some modern systematics reconstructed to be diphyletic. That would mean, there was no commor ancestor, from which only those two clades derived, the two major clades would be polyphyletic with no close relationship between them, each clade is assumed being closely related to different groups of arachnids (e.g. Psedoscorpions and Opiliones). Thus, when I talk about mites, I am talking about the clade Acariformes.
Mites of the Acariformes and body plan
In these Acariformes mites, the arachnid body construction plan was modified into three visible tagmata: gnathosoma (bearing chelicerae and pedipalps as mouthparts), proterosoma (bearing first two leg pairs) and hysterosoma (bearing last two leg pairs and opisthosoma organs).
Male (large morph) of mite Histiostoma feroniarum in dorsal view. Body division in gnathosoma, proterosoma and hysterostoma. Fixation : critical-point-dried, SEM photography, copyrights Stefan F. Wirth
Let’s talk about mouthparts, as they are an important aspect of my systematic and my function.morphological studies. Originally the gnathosoma consists of a pair of scissor-shaped chelicerae to grasp the food particles and of a pair of leg-shaped pedipalps, which mostly have mechano-sensitive and chemo-sensitive functions. But because mites colonized almost all kinds of existing habitats on earth, they extensively were exposed to the mechanisms of evolution. Acariform mites show a high range of variability regarding their morphology and their life strategies.
Mouthparts of Sarcoptiformes
Within the clade Sarcoptiformes, consisting of oribatid mites, Endeostigmata (seemingly paraphyletic) and astigmatid mites, there evolved a tendency towards miniaturization. Mites of the Astigmata are usually much smaller than one mm. Correspondingly the cuticle became thinner and softer, perfect adaptations to a life inside very tiny micro habitats, but at the same time also a limitation, namely towards more or less moist habitats due to the lack of a well developed desiccation protection. They appear inside compost, rotting wood or mammal dung, being even there very specifically adapted into very defined micro climatic conditions. They live in a world of complete darkness, which is why light sensory organs are completely lost or reduced to vestigial structures.
Inside their habitats, astigmatid mites need to reproduce, to develop through different nymphal stages until adulthood and of course to feed. Astigmata are no fluid suckers, but feed on particles, such as bacteria, algae, fungi, thus many Astigmata taxa can be named microorganism feeders.
Life-strategy of mites of the (family) Histiostomatidae
Extinct bark beetle fpssil in amber (collection Hoffeins) with phoretic mite deutonymphs. Fixation with hexamethyldisilazane, stereomicroscopic photography, copyrights Stefan F. Wirth
One of the largest family within the Astigmata clade is the Histiostomatidae, which I use since many years as model for my scientific studies. These mites are scientifically interesting from different points of view. Their ecology is characterized by life styles, which correspond to the life cycle of insects and other arthropods, to which most species have a close association. Most important aspect of these interactions between mites and other arthropods, commonly insects, is a dispersal strategy named „phoresy“. Mites use their „partners“ as carriers from one habitat to another. These habitats can often be the nests of the corresponding arthropods/ insects.
Habitats, in which mites of the Histiostomatidae develop successfully need to be moist and need to contain a sufficiant amount of microorganisms as food source. It is the most conspicuous feature of these mites to possess remarkably modified mouthparts compared to the above described standard equipment of an acariform gnathosoma.
Mouthparts of the Histiostomatidae
Mite Histiostoma sp. (sapropel around ponds, female, Berlin) feeding from a substrate surface inside its original habitat. Videography in 4K, copyrights Stefan F. Wirth
The character conditions of the gnathosoma were one of the reasons, why I at the beginning of my phd thesis in 2000 decided to put my research focus on this mite family, being worldwide in major still unexplored.
The chelicera modified into a dagger-like structure being formed by the fixed part of the former scissor-like organ, named the digitus fixus. There is a variability of shapes of this digitus fius-chelicera-ending within the Histiostomatidae . It can appear „simple-dagger-like, simple formed with a hook-like ending or having cuticular dentations of specific numbers and sizes along the lower edge of the digitus fixus.
As typical for mites of the big clade Astigmata, the pedipalps are reduced in size and almost immovably ventrally and dorsally connected with each other. In Histiostomatidae, the third pedipalp article is additionally distinctly bent sidewards. Their front sides bear more or less complex arrangements of flexible membraneous structures, which can morphologically differ between taxa or even species, thus giving them a systematic relevance. I named these membrane-organs „palparmembrane“ following the nomenclature, introduced by R. Scheucher in 1957. These membranes can be devided into fringes or being lobe-sphaped and can cover the last pedipalp article dorsally and/or ventrally. My histological analysis from 2006 indicated that these membranes are shaped by the enditesof the pedipalpal coxae.
Complex mouthpart apparatus
Thus Histiostomatidae possess a bizarre mouthpart apparatus being unique within the Acariformes and representing an amount of characters, which from the phylogenetc point of view can be reconstructed to have evolved in the stem species of that family (so called apomorphies).
Mouthpart apparatus as multifunctional organ
Mite Histiostoma sp. (male left, female right) feeding from a substrate surface inside its original habitat. Fixation with hexamethyldisilazane, SEM photography, copyrights Stefan F. Wirth
This gnathosoma is a multifunctional organ with the main function to select specific microorganism particles out of their liquid environments. When observing a histiostomatid mite with a sufficient high magnification walking along on a smooth water agar surface, on which bacteria and fungi growth was stimulated before, then occasionally trails can be seen around the walking mite, indicating that the gnathosoma was hold mostly leaned downwards towards the ground, pushing the microorganism cover along in front of the mite’s body. I interpreted this as an accumulation of food in order to gain more nutrients all at once. In my early papers, I described this as the typical feeding behavior of histiostomatid mites with the membraneous appendages acting like rubber sliders in the meantime. But as newer analyses showed is that such observations do not describe the full equipment of possible applications of the mite’s complex filter-feeding apparatus.
Membraneous structures create an underpressure to incorporate food
Mite Histiostoma ruehmi mouthpart endings with palparmembrane in ventral view. Fixation with hexamethyldisilazane, SEM photography, copyrights Stefan F. Wirth
More recent experiments with a higher videographic resolution and more suitable light conditions than 10 years ago (through-light and up light or one of them depending on the setting) showed that the palpar membrane structures , which more or less surround the entire fore-part (anterior part) of the gnathosoma can act like suckers: When the mite presses its front end of the mouthparts to the underground, an underpressure can be formed based on these membraneous structures. This seemingly facilitates the incorporation of nutrients in that area.
Note from January 2020: In retrospect, I do not consider it sensible to superficially describe the feeding behavior using the palpar membrane at the edge. A precise videographic analysis of individual images exists and is currently being developed into a scientific paper.
Aspects of the histiostomatid feeding behavior, including using the membranous components at the anterior end of the mouthparts (pedipalps), can partly be seen in the video below.
Mite Histiostoma ruehmi and an undetermined species feeding from a smooth artificial substrate surface and performing an underpressure to incorporate food. Videography, copyrights Stefan F. Wirth
Mite Histiostoma cf feroniarum feeding in its original substrate, fixed with hexamethydisilazane, SEM
copyrights Stefan F. Wirth
Mite Bonomoia opuntiae feeding from the surface of a substrate mount inside its original habitat. Rounded particles might represent yeast bodies. Fixation with hexamethyldisilazane, SEM photography, copyrights Stefan F. Wirth
In my early postdoc-years, still at the FU Berlin, I performed experiments in order to fix mite activities inside their original substrates by filling such a mite-substrate-setting up with 1,1,1,3,3,3-hexamethyldisilazane and warming the corresponding small experimental dish, until the chemical was vaporized. I then sputtered the conserved setting with gold and studied the details on it via scanning-electron-microscopy. Occasionally, mites were shrinkled or deformed after this procedure, but sometimes they stayed in shape and did seemingly still remain in their last activity positions. I several times could take SEM photos, showing that (well visible only in adult mites due to their size) mite specimens can insert their (distal) chelicerae-endings into bigger heaps of substrate (obviously full of nutrients) and use the entire laterally bent pedipalpal articles, including the connected palparmembranes, to lean it against the substrate surface, either to stabilize the chelicerae movents or even to support the incorporation of nutrients again by forming a slight underpressure, or both.
Mite species Bonomoia opuntiae
Early observations during times of my phd-thesis on the mite Bonomoia opuntiae could show that the mouthpart apparatus of this terrestrial/semiaquatic mite works well also under water or inside a watery juce of decomposing cactus pieces. There even a filter function comparable with a fishing net was hypothesised, but so far was never studied in detail. The very distinct fringes along the palparmembrane lobes in this mite species might support this theory. I also studied the semiaquatic mite Sarraceniopus nipponensis feeding inside watery environments (normally the digestive fluids of Sarracenia pitchers), again never focussing in detail in how excactly the feeding mechanism works.
A putatively new species
The herewith presented video shows behaviors of a female of the putative new species Histiostoma sp. , which I discovered in beginning of 2019 in sapropel around ponds inside an old gravel pit area in the Berlin forest Grunewald. The footage is presented in slow motion. The question was about how motile the whole gnathosoma apparatus in a histiostomatid species can be and what kinds of movements occured. As the settings, which I in early years of my mite studies used for videographic studies, were simplyfied and thus unnatural (smooth agar surfaces), I thought it being necessary and important to capture behaviors in a complexly sculptured habitat, namely surfaces of decomposing potato pieces (on which most histiostomatid species use to develop well).
It was visible, based on the specimens of my video of this species, that histiostomatid mites can be able to lift up their entire gnathosomas on a sometimes even higher position than the levels of the rest of their bodies. Additionally the gnathosoma can be turned to the right and to the left. Up and down as well as sideward movements of the whole feeding apparatus were often performed and represented obviously flexible reactions of the mite to the surface structure of the substrate and to the availability of suitable nutrients. In this context I was also interested in details of the movements of the chelicera tips themselves.
Chelicera endings (digitus fixus)
Although they can be used dagger-like and be accurately inserted into muddy substrate mounts, chelicera tips will also appear in a very fragile and seemingly careful way, when palpating the surface of the substrate underneath. Such chelicera movements are visible in the footage of this video, presented in slow motion (about 25 percent of original speed) and in a digital magnification. I interpret this visible fragility caution of the chelicerae as one option to discover suitable food sources. Other important organs perceive the mite’s environment chemically, modified setae, namely the so called solenidia, which might additionally recognize profitable microorganism sources.
Mite Histiostoma feroniarum feeding from substrate mounts inside its original habitat (A-F). Rounded particles might represent yeast bodies. D = distal chelicera endings (digitus fixus), holding food particles, fixation with hexamethyldisilazane, SEM photography, copyrights Stefan F. Wirth
Berlin is an unusually green metropolis. Besides numerous urban park landscapes and the huge forest area Grunewald, there is a unique countryside north of Berlin, including the area of the old village Lübars, being surrounded by numerous fields (Lübarser Felder) and a stream pasture landscape, named Tegeler Fließ, with bog meadows.
Nature sites Lübarser Felder, Arkenberge, Schönerlinder Teiche in 4K, copyrights Stefan F. Wirth. Please also like my video on Youtube.
Mounts Arkenberge and pondlandscape Schönerlinder Teiche
In the northeast, around the urban village Blankenfelde, the currently highest elevation of Berlin can be found, the Arkenberge. Originally, they represented a chain of smaller mounts as natural remnants of the Weichselian glacier. One of these mounts is especially conspicuous and is acually prepared to become accessible for people and forms with a height of 122 m over NHN the highest mountain of Berlin. It represents despite of its natural origin a rubble landfill site, which was formed beginning in 1984.
Adjacent to the Arkenberge, several wetland areas attract nature enthusiasts for hiking tours: the pond landscape „Schönerlinder Teiche“ (Brandenburg) and the lake Kiessee Arkenberge.
Lowland area of the stream Tegeler Fließ as remnants of the Weichselian glacier and adjacent calcareous tufa area
The stream Tegeler Fließ is a wetland nature site with a high biodiversity of plants and animals. It is surrounded by different types of bog meadows. The Tegeler Fließ lowland is also a result of the last glacier period.
The stream lowland is additionally adjacent to a calcareous tufa area, which is well visible from top of the Arkenberge. Calcareous springs and calcareous tufas created here calcareous rush- marshes with an interesting biodiversity of for example species of mosses and snails.
When a person was illegally harmed, then I expect him or her as the victim of a crime in most imaginable cases being immediately aware of something having being undoubtfully wrong, independent of the victim’s age. There might be cases and reasons, such as for example shame that can prevent an official accusation made by the victim, for a while.
But remembering serious sexual crimes only decades later, exactly, when the career is unstable enough to need a major attention, then doubts should be advised.
Documentary „Leaving Neverland“, a witch-hunt?
The 2019 documentary film „Leaving Neverland“ by the British director and producer Dan Reed is actually capturing a major attention after it was presented at the Sundance Film Festival on January 25 in 2019. The co-production between the UK Channel 4 and the US Home Box Office (HBO), presents the alleged stories of two men: Jimmy Safechuck, who performed as child in a Pepsi commercial with Michael Jackson and Wade Robson, a today dancer and choreographer. They both claim to have been over years repeatedly sexually abused by the King of Pop.
Singer and performer Michael Jackson again accused of paedophilia, a modern witch-hunt? Photo-rights: German Wikipedia
Michael Jackson won all trials against accusations of paedophilia. No indications towards sexual crimes remained. Let’s say except of the unusual and for some people’s eyes bizarre life-style and look of the singer and performer, who very obviously simply liked children in legal and natural way. In his most famous music video, „Thriller“, he appeared as a monster. Obviously the monster that so many conservative, intolerant and uninspired people want to see, even today. The modern trends of an exuberant extreme-feminism contributes to these monster-desires. Some of these hardliners generally fight for an anti-male-agenda. All males are suddenly monsters with uncontrollable sexual pressures, which they permanently practise against everything and everybody. And if they want to imagine a superlative of all these monsters everywhere, then Michael Jackson fulfills enough clichés to act as a convincing monster, even years after his death.
Aerial photography of Jackson’s „Neverland-Ranch“, photo-rights: German Wikipedia
The reaction of the „US Weekly“-journalist Mara Reinstein is absolutely according of very modern ideas of justice, it’s all about, what you feel, not what you know. Best is, when it’s against males and somehow in context with sexual accusations. That’s why she informed the world via her Twitter-account, how sick she felt in her stomach after watching the premiere of part 1 of the documentary, and how very credible the victims were coming off. I wish Mrs. Reinstein a very speedy recovery, and I think she is a very great role model, when it’s all about credibility.
#MeeToo, a modern (male) witch-hunt?
Since mid October 2017 a special hashtag overwhelmed the world: #MeToo. Suddenly countless famous male film-makers and artists became victims of sexual-abuse-accusations, using the same patterns mentioned above. But is the term „victim“ always correct in that context? Yes it is. Does that mean that all accusations were false accusations? Unfortunately not. But all modern legal systems (at least in occidental countries) require a trial, which judges against the accused. Judgements in the run-up to a court hearing or even without any court hearing at all are illegal, and in the worst case make a perpetrator as culprit indeed to a victim.
Character assassination and bullying!
When normal people and not a court judge somebody’s alleged crimes with existential consequences for that person, which are irreversible even after a later non-guilty-sentencing by a court, then this needs to be named: character assassination! It is a moral offence, which is also often called bullying, an offence, which is mostly not considered liable to prosecution, incredibly!
Witch-hunt in the Middle-Ages
From the biological point of view, humans are not as social as they are supposed to be. Almost all human skills that differ us from other Great Ape species evolved in smaller populations. Homo sapiens is until today not perfectly adapted in living in extreme big and complexe communities. Specific behavioral characters, evolved in prehistoric times, appear under modern conditions even more distinctive. These are laziness, egoism and unscrupulousness.
Malleus Maleficarum, „Hammer of Witches“, treatise on witchcraft by Henricus Institoris, photo-rights: German Wikipedia
Dangerous and sinister characters from the medieval period even towards the early modern times, exactly knew, how to make use of these unfavourable human behavioral tendencies. When for example the German churchman Henricus Institoris, better known as inquisitor Heinrich Kramer, in the late 15th century began to sow hatred between German families, friendships, neighbors and cohabitants, then he just needed a quite simple strategy to successfully perform his hysteric witch-hunt: When he arrived in a city or a village, he asked for denunciations. And he got stacks of them, what easy way it was to get rid of a competitor, an unbeloved family member or an uncooperative rich elderly lady. To officially accuse them as witchcraft was all they needed to do in order to eliminate their own people. When the real switch is pressed, humans can unfortunately still easily forget all mercy, solidarity and humanity.
I am standing in Berlin. The sky is a grey monotony. And while tiny waves gently wash around the little sandy beaches, tree skeletons surround the hidden bays on the Havel river. A semi-lucid vapor is covering the branchage of leafless treetops, already early in the afternoon. It is December in Berlin. The entire spectrum of bright summer colors is overlaid by muddy shades. Only larger groups of pine trees gleam in a greenish-black out of a giant cemetery of seemingly inanimate bodies of beeches, oaks, birches and maples. The cry of a heron in a far distance, but where has all the colorful and manifold life gone?
T. S. Eliot (1888-1965) wrote („Journey of the Magi“):
„A cold coming we had of it, just the worst time of the year For a journey, and such a long journey: the ways deep and the weather sharp, The very dead of winter…“
Shakespeare (1564-1616) on Sonnet 97:
„…What freezings have I felt, what dark days seen! What old December’s bareness everywhere!…“
Seeming emptyness of a Forest-waterside landscape in winter, copyrights Stefan F. Wirth, Berlin December 2018. Please like my video also on Youtube, in case you really like it.
Bareness, emptyness, death, attributes being combined with winter since mankind exists. From the evolutionary point of view a serious problem that early humans had to master. The seemingly emptyness was for them a very real lack of sources. They needed to prepare the winter time, food needed to be stored and protecting clothes to be stiched. There was no well organized international trade of goods, no fresh apples and pears in winter, no cheap winter jackets made in China. Winter meant to fear for the basic survival.
Today we live a different life, being independent from the seasons. Life today means for us to fear for the basic survival of our environment. What are the effects of a global climatic change? What the effects of our environmental pollution? What changes are independent from all that and just represent natural processess as they happened again and again since about 470 millions of years, when the first plants appeared on shore?
Most life does not disappear in winter, it just hibernates – alive!
The Berlin nature refuges around the forest Grunewald-terrain are interesting due to their complex mosaics of different habitats close to each other. Forest Grunewald in Berlin and the sandy beaches and bays along the Havel river offer space for lizards, an interstitial insect fauna, dry grassland visitors such as butterflies, wetland animals like frogs and newts, aquatic inhabitants like river lampreys, numerous bird species and inhabitants of wood in all kinds of decomposition stages such as bark beetles, longhorn beetles or hermit beetles.
Some animal inhabitants of the Grunewald/ Havel-area in summer migrate during the winter season, but most species stay. They hibernate and are even now in December still there.
Many birds show a strict migration behavior to avoid northern winters, others migrate in greater numbers, while some specimens stay, and some migrate only over smaller distances. Which of those migration behaviors is exactly performed by which bird species might depend on climatic conditions and is object of scientific research. NABU for example regularly starts projects, to which the general public can contribute with own observations. One of them takes place in early January and is named „Stunde der Wintervögel“ („the moment of winter birds“).
Common cranes Grus grus and greylag geese Anser anser normally migrate over bigger distances and numerous bigger routes towards southern winter refuges. Especially cranes are in summer for examples inhabitants of the Havelland Luch, thus prefer areas more western of Berlin. A trend was observed by ornithologists that more and more often, obviously corresponding with a global warming, troops of crane specimens stay instead of migrating southward.
Migration behavior of common cranes and greylag geese in Linum, autumn 2018, copyrights Stefan F. Wirth
Female of the red-backed shrike in Berlin (Köppchensee). The bird is a typical long-distance migrating animal. Copyrights Stefan F. Wirth, 2018
The red admiral butterfly Vanessa atalanta is known as a migrating insect. The „normal“ case is that migration from Southern Europe towards Central Europe is performed in spring. There, a summer generation develops and in autumn either tries to migrate back southward or to hibernate as adult butterfly, where it hatched, for example in Germany. But specimens mostly do not survive their tries to hibernate during our cold winters. This makes the admiral to a rare example of our summer-fauna, which over here partly indeed dies out before winter begins. The migration routes of populations throughout Europe is still topic of research. The migration behaviors seem to change corresponding to a global warming.
Admiral butterfly in Berlin, copyrights Stefan F. Wirth, 2018
Also the river lamprey Lampetra fluviatilis obligatory needs migrations over bigger distances. But these migrations do not correspond primarily with our cold seasons, but instead with the complexity of its life cycle. Larvae, which differ morphologically from adults, hatch in our freshwaters and develop as filter feeders within about three years, in which they hibernate inside their aquatic freshwater habitats. They then migrate after a morphological metamorphosis towards the Sea. There they live as ectoparasites on fishes until they reach sexual maturity and then return into freshwater-rivers to reproduce and finally die. It is still subject of research, whether they return for their reproduction to the areas of their original larval development.
The sand lizard Lacerta agilis hibernates in hideaways, which are able to hold a temperature around 5°C. There they fall into winter numbness due to their unability to regulate their body temperature independently from the environment. Juveniles and adult genders start their hibernations at different times.
Sand lizard juvenile, found in Berlin Grunewald/ Teufelsberg, copyrights Stefan F. Wirth
Toads and frogs hibernate after finishing their metamorphosis, juvenile and mature specimens spent a diapause as a total numbness such as in lizards. Amphibians and lizards are poikilotherm, thus their body temperature corresponds to their environment (some monitor lizards Varanus were found to have physiological abilities for a limited self regulation of their temperature, which is an exception within the taxon big Squamata).
Marsh frog Pelophylax ridibundus, pool frog Pelophylax lessonae and edible frog Pelophylax kl. esculentus survive the cold season in hideaways, which maintain acceptable environmental temperatures. While pool and edible frog hibernate on land, the marsh frog spends its diapause in aquatic habitats. Skin respiration then plays an even more imortant role, which is why these frogs require a high availability of oxygene. The edible frog is even from the evolutionary point of interest, as it represents a hybride between two closely related species, namely marsh and pool frog. It is in many of its populations non reproductive with other hybrides and needs one of the parental species to reproduce. But interestingly triploid specimens of the edible frog sometimes develop in populations and bear the complete genomic information of one of the parental species. These edible frogs can reproduce with other hybrides They can be found throughout Berlin. Such specimens are difficult to be determined morphologically, as they resemble in their outer appearance either to the marsh or the pool frog.
Insects hibernate in different developmental instars, if holometabolic, egg, larva, pupa and adults are options, if hemimetabilic eggs, nymphs or adults perform the winter diapause. Some insects can even hibernate in all of their developmental instars.
The quite common red-banded sand wasp Ammophila sabulosa for example is part of the insect interstitial fauna and does not practise brood care, but maternal care. Females built up several single nests up to 20 centimeters into the soil, each of them containing only one cell for the deposition of always one egg. As food supply they hunt caterpillars preferrably of Noctuidae, stun them with a sting and carry them to their nests, which will be closed with soil particles afterwards. The last brood hibernates as pupa or larva inside the nest.
Sand wasp Ammophila sabulosa in Berlin, copyrights Stefan F. Wirth, 2018
The grasshopper Sphingonotus caerulans is a thermophilic species, which is a typical inhabitant of sandy areas in Southern Europe. It also appears in Berlin. Its eggs are deposited into deeper soil layers and hibernate there.
Grasshopper Sphingonotus caerulans, male, found in Berlin (Köppchensee). Copyrights Stefan F. Wirth, 2018
The common woodlouse Oniscus asellus for example hibernates as nymph or mature adult in hideaways inside deeper soil layers, dead wood or compost. These terrestrial curustaceans become inactive, when colder temperatures appear. Specimens can live over several years (usually about two years).
An example for a woodlouse, in this case a mediterranean species of genus Porcellio, copyrights Stefan F. Wirth, 2018
Hibernating animal communities
Communities of different animal species often hibernate altogether. I focus here on inhabitants of micro habitats. Especially long living insect nests can bear greater numbers of cohabitants. But also deadwood or compost bear many different animal species side by side.
Nests of the red wood ant Formica rufa represent complex animal communities, as it is typical for ant nests generally. Besides ants and their brood noumerous nematode and mite species inhabit nest mounts of F. rufa. Additionally different larvae of other insect taxa can be members of the ant community, I even discovered the larvae of the green rose chafer sometimes inside red wood ant nests in the area of the Berlin forest Grunewald. Also several species of pseudoscorpions are known to science to be adapted for a survival in nests of F. rufa in Europe: commonly found are for example the species Allochernes wideri and Pselaphochernes scorpioides. Pseudoscorpion species of genus Allochernes are known to practice a dispersal strategy named phoresy. They use bigger and better motile insects as carriers and that way are transferred to new habitats. Besides ants, their suitable phoretic carriers seem to be dipterans. Also different mite and nematode taxa inside nests of the wood ant perform phoresy. A mite example is the species Histiostoma myrmicarum (Acariformes, Histiostomatidae), which seems to be carried by ants and eventually additionally also by other arthropodes.
The larva of the green rose chafer inside a nest of Formica rufa, copyrights Stefan F. Wirth, 2011
Mite Histiostoma myrmicarum (Astigmata) collected from its hibernation habitat in the soil underneath an old oak in Berlin forest Grunewald, copyrights Stefan F. Wirth, 2018
Formica rufa itself hibernates inside its nest in absence of eggs, larvae or pupae. Only the queen and workers remain during the cold season. Not much is known about other nest inhabitants. More research is needed.
Typical ant cohabitants (with Formica rufa) do not necessarily need to hibernate inside their ant nests. I collected deutonymphs of the mite Histiostoma myrmicarum in winter 2017/18 from soil (some centimeters deep) underneath an old oak in the absence of ants and their nest. The well scleotized deutonymph (phoretic dispersal juvenile stage) might represent the hibernation stage.
The advantage for organisms, living in ant nests, is a higher and constant temperature due to the ant worker’s nest-care-activities. Additionally the defensive behaviors of ants offer protection for those organisms being adapted (based on evolution) to survive inside ant nests.
Due to suitable temperatures, many organisms inside nests of the red wood ant might stay even active in winter. Interactions between ant nest-cohabitants can be very complex. An example is the Alcon large blue butterfly Phengaris alcon, being adapted to other ant species: Myrmica rudinodis and M. rubra. The caterpillar resembles an ant worker due to the morphology of its cuticle and the production of ant-similar pheromones. Ant workers fail for this imitation, carry the caterpillar into their nests and feed it. The butterfly’s larva hibernates inside the ant nest as larva, molts into pupa in the subsequent spring season and finally leaves the nest as adult butterfly. Still inside the ant nest, the caterpillar can become a victim of the parasitic wasp Ichneumon eumerus. Its female invades the ant nest, only after recognizing that caterpillars of the blue butterfly are indeed inside. It then confuses the antworkers due to the release of different chemicals and then attaches its eggs to the caterpillar. The wasp’s larva hibernates there and molts into its pupa inside the host’s pupa. The adult wasp afterwards leaves the ant nest.
Phoretic mites of the taxon Astigmata inside a nest of Myrmica rudinodis, found on island Usedom, copyrights Stefan F. Wirth
Bark beetle galleries
Numerous mite and nematode species live inside the galleries of bark beetles. Such a complex fauna is known for many bark beetle species. Additionally the larvae of different other insects can be cohabitants. Depending on the species, they can perform all kinds of life-strategies: being predators of adult bark beetles or their offspring or of other gallery cohabitants, they can also be microorganism feeders and prefer the bark beetle galleries due to its ideal warmth-isolation or due to the specific micro-climate that is created there by the activities of all different inhabitant activities. Besides animals, also fungi and bacteria contribute to that climate.
Bark beetle Hylurgops ligniperda and phoretic mites, copyrights Stefan F. Wirth, 2016
Wood associated nematode Diplogaster sp. found in the tree fungus Laetiporus sulphureus in Berlin, copyrights Stefan F. Wirth, 2016
Mite deutonymphs of the Histiostomatidae mites inside the galleries of the bark beetle Tomicus destruens in Italy, Vesuvio National Forest, copyrights Stefan F. Wirth, 2016
Bark beetle Ips typographus with some of its gallery-cohabitants, such as phoretic mites, found in SW-Germany (Saarland), copyrights Stefan F. Wirth, 2015
Furthermore the composition of species in a bark beetle gallery changes with an increasing age of a gallery. Secondary infections are often performed by other wood parasiting beetles, after the bark beetle brood finished its development and left the gallery. A secondary parasitism can for example be performed by longhorned beetles.
The bark beetle Dendroctonus micans for example infests several conifer species: Picea, Abies, Larix and Pinus. This bark beetle can hibernate in all its instars: eggs, larvae or adults. Adults can in spring sometimes be found in specific hibernation-chambers. In a research project with russian collegues, I isolated beetles of that species in the early spring season in Siberia (Russia) out of such a chamber on Pinus silvestris. Adjacent to attached substrate particles, I found nymphal stages of the phoretic mite Bonomoia opuniae, a species of the Histiostomatidae (Astigmata), which was even new to science at that time. I described this species, which I so far only know from those siberian samples. It is still unknown, whether it also appears in Central Europe.
The nymphal stages (protonymphs and tritonymphs) of that mite species might represent the hibernating instars. They were not fallen into a numbness after the collection and even remained active in a refrigerator, where my samples were stored subsequently for a while. I doubt that the mite in winter can pass through different generations as it would happen in a warmer climate, because the found mite nymphs appeared -also active- still rather weak in their cold environment. Thus I assume these nymphs to hibernate throughout the winter season. But there is still much research missing about the ecology/biology of bark inhabiting mites.
Adult beetles of Dendroctonus micans with deutonymphs of Bonomoia sibirica, Tyumen/ Siberia, copyrights Stefan F. Wirth, 2017
Decomposing detritus (mostly dead algae debris) of marine organic material, laying onshore more or less close to the water line, containing seaweed or cadavers of aqatic animals, is named wrack. Wrack can appear under different kinds of ecological circumstances. In case, it would be in permanent contact with sea water, it might be mostly decomposed by marine organisms. But due to different reasons, wrack can land apart from a permanent sea water contact or even no sea water contact at all any more.
Here mostly terrestrial organisms with a tolerance for salty conditions would inhabit and decompose this piece of detritus. Sandhoppers (Cristacea) are known to switch between wracks of different conditions. They can for example carry mites or nematodes from one wrack habitat to another. Dead organic material generally always needs to be decomposed by living organisms, otherwise the whole ecological system would be harmed.
A specific kind of micro habitats
A small habitat, which would dry out after a while and thus exists only for a limited time, is called ephemere biochorion. Organisms being adapted to live there, must have adaptations, to leave their habitat by time to avoid desiccation. One option is a life strategy, which is named phoresy. Weaker organisms, unable to desperse themselves efficiently use other animals, such as winged insects, to take a ride on them to new habitats with suitable conditions for a development. Generally phoretic organisms can for example be represented by different groups of mites (e.g. Uropodida, Gamasina, Tarsenomidae, Scutacaridae, some Oribatida, Astigmata) and nematodes (Rhabditida).
Mites and nematodes
In case of wrack, decomposing close to the waterline, but without or only occasional water contact, Pellioditis marina (Nematoda, Rhabditida) is for example known as phoretic inhabitant along German coasts. Worldwide, crypitical sibling species of P. marina were meanwhile discovered. Depending on the exact situation of the wrack, also aquatic nematodes could appear there for a while. I couldn’t determine the nematode in my footage unfortunately at all, because I did not prepare slides of them enable a larger microscopic magnification. Phoretic mites can be associated with sand-hoppers (Amphipoda, Crustacea) and thus appear in wrack. Mites of the Histiostomatidae (Astigmata) were for example discovered in such a context by some researchers.
Mites of the Ameronothridae (Oribatida), sand-hoppers and dipterans
I so far never found them randomly, but also didn’t explicitely seek for histiostomatid species until now. My sample did not contain any Astigmata or I at least didn’t find them. Common inhabitants of decomposing wrack are oribatid mites of the Ameronothridae. This taxon with a worldwide distribution is charaterized by specific adaptations to deal as terrestrial organisms with (partly extreme) salty marine conditions. They are mostly algae feeders. Some species are known to appear in wrack. The sample, which I collected in context of the so called „Geo Tag der Natur 2018“ (Geo (journal) day of nature) in Norddeich Mole (East Frisian coast of Germany) contained many specimens (ca. 40, sample size of about 20×20 cm) of the Ameronothridae-species Ameronothrus sp.. My footage shows only one living specimen, as all had died until I began my filming activities.
Inhabitants of decomposing algae tissue along a beach at German North Sea, all copyrights Stefan F. Wirth
But I preserved several dead specimens for scientifc purposes. Ameronothridae might, according to literature, use phoresy via birds, but also might disperse themselves over smaller distances, due to their well developed cuticle, protecting against desiccation, and their rather fast locomotion abilities. Larvae of different species of flies (Diptera) developed inside my sample and hatched under my laboratory conditions after about two weeks. They intensively contributed to a fast decomposition of that organic marine tissue. Sand-hoppers were by the way not found at all.
Bacteria and protozoans
Bacteria are most important decomposers. But the function of protozoans (here e.g. Ciliata) in regard to the process of wrack degradation, which could still be isolated alive after about two weeks of decomposition, is unknown to me. My sample was found almost on top of a dike, meters away from the highest tide in that area and consisted mostly of the seaweed Fucus vesiculosus.It also contained sea gull feathers.
Berlin/ Norddeich Mole June/August/November 2018 Copyrights Stefan F. Wirth