Leaders of the German national subsidiaries and the federal government, above all the chancellor Merkel, ask for stricter contact limitations. Although the current conditions in form of a part-lockdown as reaction to increasing numbers of covid-19-infections throughout Germany restrict numbers of people, who are allowed to meet up inside or outside as well as the numbers of households, to which they belong, already remarkably. All public places for socializing and cultural activities are closed, also sport clubs, public swimming trainings or outdoor sport activities in greater groups are impossible. That means, bars, cafés, restaurants are closed. Theaters and opera houses as well. Especially „smaller“ stage artists suffer existentially.
Only the german football (soccer) is still omni-present in the news reports. I don’t know why. Seemingly their games can happen under limited circumstances. I am not interested in football at all. It is also not football, which is since the beginning of the human evolution a major fundament of our societies, it’s art. Art is not only creativity, it also stands for legal criticism against all aspects of social and political interactions. Thus something important is missing. And private life? It is already in the recent part-lockdown harmed in a way, that acts against the human biology as social primates. Not only old people in retirement homes live almost under conditions of a dentation centre, also single-persons of all ages, living in smaller apartments, need to tolerate loneliness. The Homo sapiens is a social species, too much isolation can cause longtime-damages, emotionally, psychologically, in case of older people even physically. Not to forget those citizens without any kind of home. The many homeless people, especially in Berlin, are very sensible victims of recent restrictions. Are all these risks, the Germans actually are exposed to, worth to happen? I think yes, they are, if it is for a limited time and under circumstances, which do not cause more damages than the virus infections themselves. It is fact that the new corona virus can be harmful to people of all ages, especially when there are significant medical histories existing. But as all these sanctions represent limitations of our basic laws, it is important that all these limitations are reversed when the pandemic is over.
Critical questions are allowed. They are also important and necessary. And you even do not need to be a believer of modern religious movements like Qanon. I for example ask for the relevance of indirect contacts between individuals for the still too high infection numbers. When I see super markets, forcing their clients to use shopping baskets or trolleys without employees existing, who desinfect each of them before and after use, then I hear the virus clapping amused its non existing hands: „We couldn’t get you so far? Here we are, left behind from hundreds of people per day, who touched this basket or this trolley before!“ Are such contra- productive rules necessary, even when the argument is that baskets and cars force a proper distance between customers? Also in U-Bahn cars (subway etc.), trams or busses, an indirect virus transfer between passengers needs to be much better prevented . Shouldn’t it be possible to employ people, who permanently walk through the cars and desinfect seats and handrails whenever possible?
A dark world? Copyrights Stefan F. Wirth, December 2020
As a natural scientist and active researcher as well as reviewer for scientific journals I know that statistics generally bear many reasons for critical questions. It can easily happen that submitted natural-scientific papers in peer-review journals are rejected by the reviewers based on doubtful or insufficient or even wrong statistical methods. We read or hear in the news permanently about growing incidence numbers. Many people might think that these are given facts, about which questions or critical remarks are not appropriate or necessary. Based on the limited informations via the popular media, the following questions are very sure and from a scientific point of view of interest: How many people of a specific region, for example a district of Berlin, were tested and how many were not? In case of higher numbers of non-tested citizens, statistical means need to be used in order to extrapolate to the whole population of the corresponding region. It is important that a statistical variance within the tested people is guaranteed. There would for example be a lack of a sufficient variance, if it came out that specific genders or specific occupational groups had more reasons or even forces to participate test procedures than others. Statistical tests always have a defined probability of errors. But more and illegitime errors can for examples be added, when research institutions need to provide a defined high number of data in a defined period of time, especially when the procedure is well paid and „success“ thus economically important. According to my knowledge and experiences, scientific studies can only be finished, when they are finished. Evaluations in defined time periods with defined numbers of sample sizes are prone to error. I know from commercial institutions for market and opinion research that the time pressure is often or sometimes used for the disadvantage of a sufficient variation of test persons. Some facilitate their work by contacting such people for phone interviews, who’s telephone numbers were part of a commercial phone number trading. That means they buy existing phone numbers instead of generating them via a random number generator. Additionally/ or they facilitate statistical methods, which were developed to guarantee a variation of test persons. An example is the „Geburtstagsschlüssel (birthday key)“, which requires from the interviewer to strictly only talk to that person of a household, who was the last to have birthday or alternatively will be the next to celebrate it. If that person, so the rules, is not available, the interview cannot happen. Based on economic interests of the institutions and the time pressure, facilitated versions of the „birthday-key“ are sometimes used. Such as: asking for the birthday person in the household, and if the person is not available interviewing everybody available instead, or even leaving the birthday key completely out. Results of such „manipulated“ evaluations can be representative nevertheless. But they also might not be representative at all. There exist examples for extrapolations of upcoming electoral successes, being far removed from the real situations. What does all this have to do with evaluations about covid-19-infection numbers? I hope that independent sources regularly control the responsible research institutions regarding the proper use of statistical methods even under time pressure conditions.
In case it is made sure that indeed bars, restaurants, theaters and opera houses and not indirect contaminations elsewhere or statistical errors or manipulations cause the permanently high numbers of new infections everywhere in Germany, a total lockdown will be unavoidable. The German government and the federal state representatives will come together for further deliberations still before Christmas. This was announced in the news today. It is important that the decision for stricter measures need to take those groups of the German population under consideration, which might physically, psychologically or financially too much harmed by a full-lockdown over a longer period of time. It furthermore needs to be excluded that participating politicians have other motivations than protecting us from a pandemic virus, such as lust for power, interest in totalitarian experiments or a total lack of empathy.
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
They look without magnification more like very motile and fast running ants or very tiny grasshoppers than like arachnids. But they indeed represent relatives of the web spiders and scorpions: Schizomida, a clade of whip scorpions. They are the sister taxon of Thelyphonida, the rather well known „big whip scorpions“, which are often kept as pets in terraria around the world. Schizomida are only rarely filmed in a higher resolution quality, which is due to their small size and their almost invisibility due to their semi-transparent cuticle and their very fast way of walking or even jumping. They are additionally difficult to be filmed as they strictly avoid all lights and tend to dry out quickly, when they cannot hide themselves by time in a slightly moist substrate.
Closeups of behaviors of a Schizomid species from a greenhouse in Germany. Copyrights Stefan F. Wirth
Schizomida in Greenhouses
Schizomids represent mostly tropical or subtropical organisms. But some species are regularly dispersed into greenhouses around the world. The filmed species might be Stenochrus portoricensis, but was not systematically studied in detail so far. As all known species, which appear in greenhouses, also S. portoricensis reproduces (apart from their original habitats) parthenogenetically with females producing females without mating procedures (thelytoky). I never found males so far.
S. portoricensis: native to subtropical Zones
The specimens, which I kept since months in a small terrarium, were collected in autumn 2016 at the famous fun and wellness bath „Tropical Islands“ South of Berlin. There they are a natural part of the world’s biggest indoor rainforest. The species S. portoricensis is originally native to Florida, Mexico, Cuba, Nicaragua, Porto Rico and other localities in similar tropical zones. These microscopical tiny organisms are predators and do not harm human beings at all. According to the available organisms in a suitable size in my terrarium, they might feed on the numerous collembolans and/or mites. Especially mites of the Gamasina appear in greater numbers in my substrate, which represents the original substrate from the greenhouse. I enriched this substrate regularly by smaller pieces of fruits or vegetables to stimulate the growth of microorganisms. I keep them at room temperature (about 20°C) and with not too much moisture. I do not know, whether they reproduced within these months, but the specimens of my recent video footage represent all sub-adults.
Film set and topic locomotion
Focus of my film is to present the different ways of locomotion, cleaning behaviors and burrowing activities of these fascinating animals. During the filming procedure, I used two cold-light-lamps for a suitable illumination and an ILCE-6300 (internal 4K mode), connected to a stereomicroscope and a lightmicroscope (with uplight).
Berlin December 2019/ March 2017, 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
Mouthparts
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
Scanning-electron-microscopic experiments
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
Many tourists from overseas use to visit European cities in a much too short time. For this reason they often miss an entire picture of for example the city Berlin, when inserting an only short interstop here. Especially winter tourists can experience the German capital as a sad a grey urban being with some architectural major sites and a remarkable party life only.
Climate and landscape types in Berlin
Berlin has a continental climate and shows a completely other face in summer. It’s a very green face. Not only is the center of the city then colorfully greened by numerous urban parks, which partly lay almost adjacent to each other, but also the outskirts, in major parts covered by forests and grasslands or fields, appear like green oases.
Countryside of Berlin as aerial videography, Copyrights Stefan F. Wirth, Berlin June 2019. Please give my video on youtube a like, in case you like it.
Lübarser Felder and surrounding
Lübarser Felder is an area of agriculture, being under the management of inhabitants of the adjacent village Lübars, which represents the only Berlin village that still practices agriculture. The village has a long history and still has architectural monuments, dating back to the 19th century. Lübarser Felder lay adjacent to a nature refuge area more in the north, consisting of different kinds of wetlands, such as bog meadows or lowland fens. Lake Köppcensee as part of that nature refuge area is visible from a bigger distance in one scene of my video.
Püttberge and surrounding
The sanddune-mounts Püttberge are located in the east of Berlin and belong to the nature refuge area Wilhelmshagen-Woltersdorfer Dünenzug. The area consists of sandy mounts, some of them reaching a height of up to 68 meters. They are part of the glacial valley of Berlin, which dates back to the Weichselian glaciation, which happend between 115,000 and 11,700 years ago and covered almost the whole Northern Europe. The dune elevations of Püttberge were formed due to windblown sand inside the glacial valley. My footage shows the Wilhelmshagen-Woltersdorfer Dünenzug in a greater distance seen from the edge of the whole area. Ecologically the Püttberge are characterized by numerous plants and animals, being typical for sanddune environments.
Lieper Bucht at river Havel
Lieper Bucht is a bathing beach area at river Havel, belonging to the Berlin city district Nikolassee in the South-West of Berlin. The adjacent forest area is the huge urban forest Grunewald. The riverside of Havel in Berlin is geologically charactrized as sandy with a tendency to the formation of dunes, being like Püttberge a relict of the Weichselian glaciation. Flora and fauna are correspondingly composed. Pine trees for example are typical representatives. The nearby Havel islands Lindwerder and Schwanenwerder are visibe in my footage.
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.
The footage was captured from localities around the village Lübars in the area of Lübarser Felder and additionally around Arkenberge. Some above mentioned nature sites are only visible in a distance.
The city of Berlin geomorphologically consists of witnesses of the Weichselian glacier. The modern city itself and adjacent federal states represented end moraine areas with fluvio-glacial debris accumulations, even well visible today due to a very sandy soil composition and a corresponding vegetation, creating landscapes, which partly almost look like from around the Mediterranean Sea.
Sands carried by the glaciers towards their end positions remained in partly huge layers with a thickness of up to 20 meters or more.
Gravelpit zone and its history
Also the area of the old gravelpit zone, called „Sandgrube im Jagen 86“, in the Berlin forest Grunewald is located inside such an end moraine zone, which was represented by plates belonging to the geological Teltow-plateau. In the time period between 1966 and 1983, gravel was excavated for industrial purposes. After 1983 a part renaturation was supported by nature conservationists. In 1992 in total 13 hectares of the former gravelpit area were allocated as nature conservation areas.
Other parts of this unique landscape remained accessible for the public. They represent today popular places for leisure and experiences of nature. Especially the huge sand dune is a popular destination for families with children.
Aerial videography of the gravelpit area in January 2019, copyrights Stefan F. Wirth. Please like my video also on Youtube, in case you like it.
Gravelpit zone and its ecology and biodiversity
The whole area – nature protection and accessible zones – show a complex mosaic of different landscape types, offering numerous animal and plant species a well suitable refuge. Neglected grasslands and dry meadows are surrounded by sandy areas free of any vegetation („dunes“) and moist osier beds and wetlands with ponds. The wetlands represent breeding grounds for numerous amphids. Lizards such as the sand lizard Lacerta agilis and snakes such as the grass snake Natrix natrix can regularly be observed. Sandy habitats offer space and specific ecological conditions for a interstitial fauna, consisting for example of different bee and sand wasp species.
In total the area bears more than 300 ferns and flowering plants, 16 breeding bird species, 7 amphibian species and 188 butterfly species.
My own scientific mite research in the gravelpit area
I was performing scientific research in that gravel pit landscape during the work on my phd-thesis between 2000 and 2005. My interest was (and one of my interests is still) focussed on specific organisms living around the shoreline of ponds.
The whole area of the gravelpit landscape is a good example for ecological changes that happen naturally with the ongoing time or even being affected by climatic changes. Between 2005 and 2018, the landscape partly changed significantly. Neglected grasslands and dry meadows covered less space originally, and instead several smaller ponds existed and offered amphibs and wetland inhabiting insects additional habitats. But some of the ponds already years ago dried out permanently. Their remnants are now covered by extended dry grasslands.
In former times of my phd thesis and even today, my research interests focus and focussed on the mite fauna in and around the muddy shorelines of ponds inside this former gravelpit area. The ponds are mostly surrounded by sapropel, a seemingly black and brownish mud, which is colored that way due to the incorporation metal sulfides. These muddy areas develop due to biochemical modifications of organic material in the absence of oxygen. Different insects, especially beetles live on top of these waterside habitats or even inside. Carabids of genera Elaphrus or Bembidion represent predators, while heterocerid beetles of genus Heterocerus are substrate feeders, presumanly with a preference for diatoms. Also water beetles of Dytiscidae and Hydrophilidae inhabit these habitats.
The mites Histiostoma maritimum and Histiostoma palustre
I discovered some of these beetles as dispersal carriers for specific mites. The dispersal strategy to take a ride on bigger animals to become carried from one habitat to another is called phoresy. Mites of the Astigmata represent typical phoretic organisms. I am scientifically specialized in a specific family of the Astigmata, which is named Histiostomatidae, and I discovered the mite species Histiostoma maritimum Oudemans, 1914 on Heterocerus fenestratus and H. fusculus as well as on Bembidion and Elaphrus species insside and on top of these muddy zones. I was the first acarologist, who ever studied the biology of this mite species. I furthermore discovered another mite species that was completely new to the scientific knowledge, and thus I scientifically described it as Histiostoma palustre („palustris“ = „muddy“) in 2002.
This species deserves particularly mention due to an unusual biological phenomenon: populations show a so called male dimorphism (better diphenism). Besides males with a „normal“ morphology, morphologically modified males appear. Their second legs differ from the typical shape of a mite and are modified into clasping organs. The function of these conspicuous organs could so far only be interpreted in the context of male to male competition conflicts for a female. In such situations, I observed the organs being used as arms against other males, against such ones with and such ones without clasping organs.
Right modified leg of a male of Histiostoma palustre. Copyrights Stefan F. Wirth, 2002/ 2019
Modified leg of a H. palustre male in closed position. Copyrights Stefan F. Wirth, Berlin 2002/ 2019
Underside of a H. palustre male with modified leg. Copyrights Stefan F. Wirth 2002/ 2019
Asymmetry: male of H. palustre with only the right leg modified. Copyrights Stefan F. Wirth 2002/ 2019
Asymmetry: male of H. palustre with only the left leg modified. Copyrights Stefan F. Wirth 2002/ 2019
Copulation of a Histiostoma palustre male with both-sided modified legs. Copyrights Stefan F. Wirth, Berlin 2002/ 2019
Details of a copulation with a modified male, copyrights Stefan F. Wirth, 2002/2019
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.
Migration
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.
Birds
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
Butterflies
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
River lamprey
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.
Hibernation
Sand lizard
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
Frogs
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.
Sand wasps
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
Grasshoppers
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
terrestrial Isopods
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.
Ant nests
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
The river Havel has its source in the Mecklenburg Lake Plateau and after 94 km flows in the area of the border between the federal states Brandenburg and Sachsen-Anhalt into the big river Elbe.
Havel runs besides the already mentioned states Brandenburg and Sachsen-Anhalt also through Berlin, the capital city of Germany. On its way, the river passes several bigger and smaller lakes, which serve as water reservoirs, even in hot summers, in which many german rivers and lakes from low water levels.
In its most parts, Havel is navigable, and weirs and locks regulate water levels and water supply.
Historically, Havel since at least 928 of our Western calculation played importent roles as natural border and water route. Through the middle ages up to times of the GDR wetlands as important ecosystems were stepwise drained. In more recent times the protection of unique nature refuges is proceeding. In 2004 for example, the Naturfreunde Deutschlands and the German Fishing Federation elected the Havel area as River Landscape of the year.
In 2005 the Federal Agency for Nature Conservation (BfN) and the Nature Biodiversity Conservation Union (NABU began the land restoration to create refuges for rare bird species , beaver, river lamprey, otters and other animals and plants.
The footage of my video was captured close to the bathing beach area „Lieper Bucht“. Visible are the Havel islands Lindwerder and Schwanenwerder as well as edges of the forest area „Düppeler Forst“.
River Havel and Forest Grunewald in Berlin, quadcopter footage. Copyrights Stefan F. Wirth, December 2018. Please like my video also on youtube, in case you like it.
Forest Grunewald
Adjacent to the Lieper-Bucht area, the huge urban forest Grunewald extends over 3000 hectare between the Berlin districts Charlottenburg and Zehlendorf.
It was elected as Forest Area of the Year by the Union of German Foresters in 2015. The Grunewald ecologically has a specific mosaic of ecosystems: heathlands, neglected grasslands, dunes, dandpits and marshlands. They all bear a remarkable biodiversity of rare animal and plant species.
Geomorphologically the Grunewald area was formed by galcio-fluvial processess during the Weichselian glaciation , which endet about 11600 years ago. Glacio-fluvial sands cobver the area in layers up to 20 meters and more.
The footage of my video also shows the so called Grunewald Tower. The memorial for the German Emperor William I was planned in 1897 and finally built up by the architect Franz Schechten. The tower was finally inaugurated in 1899 and renovated between 2007 and 2011.
The footage was captured with a DJI Mavic pro quadcopter in mid December 2018.
Lake Teufelssee in the Berlin urban forest Grunewald is known since ancient times, but is even much older. This is unlike the adjacent hilly landscape, which is named Teufelsberg („Devil’s Mountain““, referring to the nearby lake). It represents an area of mounds of rubble, built up with debris of the destroyed Berlin after the Second World War. Teufelssee („Devil’s Lake“) however is part of a glacial chains of lakes, a result of a supraglacial stream from the period of the Weichselian glaciation.
Air-view footage of lake Teufelssee in Berlin. Copyrights Stefan F. Wirth, please like my video also on youtube,in case you like it.
Geomorphology of Berlin, lake Teufelssee and glaciofluvial sands
Berlin itself represents geomorphologically a push morain from the Weichselian glacier times (until 11.600 years ago). This until today explains the uniform and scarce vegetation in and around Berlin, which is due to specifically sandy ground conditions. Sand layers with a thickness of at least 20 m date back to glaciofluvial sands, being a result of the advance of a glacial tongue.
Vegetation and climatic zone
The stock of trees in the Grunewald area is dominated by oaks and pines, being well adapted to this ground composition and the Berlin geomorphology. The climate of the Berlin area is characterized as part of the temperate climate zone in the transition between maritime and continental climate. Aspects of the continental climate are predominant, which is why snowy winters as typical for the Southern parts of Germany are rare.
Instead winters are often very cold and with low precipitation unlike the hot summers, where most rainfall occurs. The winter 2018 to 2019 is following an unusually warm summer with long periods of heat and without rainfall. As a result, water bodies Germany-wide carried less water than usually. But in which intensity lake Teufelssee was or is still concerned is unknown to me. Differences to former years are not obviously visible.
Berlin recreation areas and the ancient origin of the term „devil“
Teufelssee and Teufelsberg represent local recreation areas and offer enthusiasts and families with children a popular playground in summer, and in case the lake is frozen, also in winter.
The appearance of the German word for „devil“ in Teufelssee and Teufelsberg is assumed to refer to an ancient place of worship in this area.
biologe 