biologe

Blog and online journal with editorial content about science, art and nature.

Kategorie: Wissen

Drone flights: Worth seeing nature around the fields of Berlin

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.

 

Green areas in Berlin

 

 

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.

 

 

 

Mosaic of different landscape types close to each other

 

 

 

 

 

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.

 

Videographic details

 

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

 

Diving, feather cleaning and water bathing of the Inca tern Larosterna inca


Inca terns live along the South American Pacific coast and breed along rocky coastlines of Peru and North Chile. They can be easily identified by their grey plumages, their distinctly red beaks and feeds as well by their conspicious white feather curls on the bases of their beaks.

 

Geographic distribution and life-strategy aspects of Larosterna inca

 

Larosterna inca breeds inside rocky walls of coastlines either inside rocky cavities or in old nesting holes of other seabird species. Its hunting ground is the  Humboldt Current, which is famous for its cold temperature, but also its enormous fish wealth. To increase its chances for fishing success, the Inca tern might follow sea lions, cormorants and whales  and is then hunting fishes, which were flushed up by these bigger sea animals. They also follow fisher boats to catch some rests of their fishery.

 

Phylogenetic (systematic) relationships

 

According to phylogenetic reconstructions L. inca, which represents the only recent species of its genus, branches off in the Animalia tree within the monophyletic clade of terns. Based on DNA sequences E. S. Bridge, A. W. Jones and A. J. Baker reconstructed in their 2005 paper (Molecular phylogenetics and evolution) a sister-clade relationship between Larosterna and species of the taxa Sterna, Thalasseus and Chlidonias (mitochondrial DNA was used to reconstruct the tern phylogeny).

Terns themselves seem representing an own clade (Sternidae), being for example based on characters of behavioral pattern, and are considered as a sister taxon of gulls (Laridae).

 

Filming conditions and filming locality

 

My footage was recorded in the Zoo Berlin, where terns together with other sea birds inhabit a for tourists accessible free-flight enclosure. There I captured scenes about the diving and „fishing“ behavior (specimens fished repeatedly wooden sticks) as well as their plumage cleaning activities on shore and their conspicuous plumage cleaning behaviors via extended bathing trips inside areas of low water. Size of my entire video is 4K. But parts of the scenes were originally recorded in Full HD to enable a better slow motion effect based on 100 frames per second. Such footage was subsequently digitally magnified into the 4K size to fit in the entire video project.

All behavioral activities are at first presented in a slow motion (ca. three to four times slowlier than  original speed), then in the much faster original speed.

 

Plumage cleaning

 

Plumage cleaning is part of the hygienic behaviors of birds. Feathers can only stay in full function, thermoregulation and flying, when dirt and parasites are removed regularly. Typical plumage parasites are represented by feather mites (no phylogenetic clade), which consist of taxa of the Astigmata (Acariformes) and of taxa of the Dermanyssoidea (Parasitiformes). Feather lice represent  a subclade of the (Phthiraptera = lice), named Mallophaga. The monophyletic situation of Mallophaga is seemingly doubtful.

 

Plumage cleaning and hunting behavior of Larosterna inca, video (4K9, copyrights Stefan F. Wirth. Please like my video on youtube too.

 

Putative reasons for plumage cleaning behaviors

 

I couldn’t research sufficient information about specific plumage parasites of Larosterna inca. There is indication that terns generally are relatively free of predators and parasites. Seemingly, plumage parasites of this particular species are still a more or less open research field. But the existence of a regular and visibly careful plumage cleaning might indicate a sensitiveness for corresponding parasites. L. inca can be according to literature (e.g. W. Pieters et al., Avian Diseases, 2014) fatally infested with the trematode Ichthyocotylurus erraticus.

 

Copyrights Stefan F. Wirth, Zoo Berlin July/ September 2019

Countryside of Berlin: urban green in a drone view (4K)

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, June 2019

Copyrights Stefan F. Wirth

Mite Histiostoma sp., putatively new species, from mud around ponds (Berlin) and its morphology

Gravel pit area „Im Jagen 86“ in Berlin as biotope

 

„Im Jagen 86“ is a former gravel pit area in the Berlin urban forest Grunewald. It today represents a dynamic biotope, consisting of different types of habitats: mud around ponds, sand dunes, dry grassland and forest. Since the early 2000th, its habitat composition partly changed remarkably. Out of several (smaller) ponds, only one bigger pond remained. All ponds originally were surrounded by sapropel, a habitat for different interesting organisms, such as beetles of Heterocerus, Elaphrus and Bembidion. The mite Histiostoma maritimum was commonly found phoreticaly on Heterocerus and Elaphrus. I additionally in those early 2000th described the new mite Histiostoma palustre from Hydrophilidae of Cercyon and Coelostoma, living inside the saporopel as well. Today only a few small areas with open sapropel exist. I so far did not look for Histiostoma maritimum again and don’t know, how common it still is. At least Heterocerus beetles are harder to find than in earlier years. I so far did not found Histiostoma palustre again.

 

Rearing conditions of a putatively new mite species

 

I collected new mud samples in March 2019 at different areas, but found developing histiostomatid mites in a sample from the edge between mud (sapropel) and mosses. It is a species I never found before there and which might represent a new species. Only females could be morphologically studied. Nymyphal stages (not deutonymphs) are only available as video footage. No males were found. I had added bigger potato pieces to stimulate microorganism growth as mite food into the soil sample (room temperature). After about one month, a few mites (females and proto/tritonymphs) developed on only one of these potato pieces and quickly died out shortly after my filming activities and after I could prepare a few females. I actually try to get them reared again. Due to the low temperatures in March, it is considered that these mites hibernate independently from insects in the substrate. No bigger insects could be found in the substrate, which might be the corresponding carriers. But different dipterans (e.g. Ceratopogonidae) developed, they had no mite deutonymphs after hatching in my sample.

 

 

 

 

Morphological reconstruction of females and important characters as well as behavioral observations

 

The females of Histiostoma sp. differ from other females, which I know, by the mosaic of the following characters: body conspicuously elongated with a distinctly big distance between hind ringorgans and anus, digitus fixus almost simple shaped, fringes or ridges on palparmembrane, 6 dorsal humps, unusually big copulation opening. Leg setation not yet studied. One pair of ventral setae hardly visible (not in the drawing). Nymphs were observed during burrowing activities (footage), females are may be also able to. Deutonymphs or males would be useful to decide, whether the species is new. Some species are only described by deutonymphs.

 

Berlin, March/ June 2019 All copyrights Stefan F. Wirth

Agriculture, natural countryside and stream pasture landscape north of Berlin

Berlin as a green city

 

 

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.

 

https://www.instagram.com/p/BuZUYu3FVJK/

Video footage

 

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.

 

Berlin, March 2019, copyrights Stefan F. Wirth.

 

Late winter insect life: winter aconite blossoms and dipteran visitors

When do the first insect activities in the new year occur? Can insects be active in winter, even in the presence of snow? The answer is generally yes, different insect species even use to appear on warmer winter days on top of snow layers. Examples are the limoniid crane fly Chionea belgica, a wingless dipteran, which can be observed on milder winter days on snow surfaces along forest edges in Central Europe. Also the fly Trichocera hiemalis belongs to the winter crane flies (Trichoceridae) and can be characterized by a very well developed cold resistance. It appears on sunny winter days between branches of leafless trees in swarms around invading sunlight beams.

 

The winter aconite as an early blooming flower and its biology

 

But what about insects, visiting blooming flowers? This requires the existance of early blossoms, which can grow and bloom under winter conditions. A well known example is the winter aconite Eranthis hyemalis, which outlasts the summer period only by its underground tubers. Their conspicuous yellow blossoms belong to the first blooming flowers in the year. In Central Europe, they begin to grow under suitable conditions in mid February. They require milder temperatures, but even persist in case an unusual cold snap would happen. The blossoms open only at sunshine and thus close shortly after sunset. Opening and closing is a growth process, which depends on temperature conditions. Such a phenomenon is called thermonasty.

 

The winter aconite as a neophyte in Germany

 

In Central Europe, such as in Germany, E. hyemalis is a neophyte. It is originally native to Southern European areas, Turkey, South-East-France, Italy, Bulgaria and Hungary.

The species was introduced to Central Europe (and North America) as ornamental plant for gardens. It is proven that it was in Germany already cultivated since the 16th century. The German botanist, nature researcher and medical doctor Joachim Camerarius reared the winter agonite, which he brought from Italy, since 1588 in his backyards.

 

Common pollinating insects

 

Pollinating insects of E. hyemalis are flies, bumblebees and bees. To reach the nectar inside the blossoms requires a proboscis length of about two mm, which is mostly given in bumblebees and bees.

 

Flowerbed in Berlin urban park Schillerpark

 

I documented via my videography (4K) and photography a smaller area of winter aconites in front of a wall at urban park „Schillerpark“ (honoring the German poet Friedrich Schiller) in Berlin. The bright bricks of that wall reflected efficiently the solar warmth and thus created suitable conditions for a late winter flowerbed full of life.

 

Video with winter aconite blossoms and pollunating flies, copyrights Stefan F. Wirth.

 

Most abundant insects in that winter aconite bed

 

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Western honey bee, copyrights Stefan F. Wirth

 

The western honey bee Apis mellifera was often seen on blossoms, but unfortunately was not captured via video footage. Our honey bee hibernates in a so called winter clusters with lower temperatures and low activities in workers. Beginning in late winter/ early spring, workers increase the nest temperature due to body movements up to 35°C. This is exactly the body temperature, workers need to fly out and collect first nectar and pollen, for example from the winter agonite.

 

https://www.instagram.com/p/Bt_oaLtF5NH/

Drone fly on blossom of the winter aconite, copyrights Stefan F. Wirth

 

The drone fly Eristalis tenax belongs to the hoverflies (Syrphidae). Their larvae develop in watery environments, where they use their conspicuous snorkel tube to breath air at the water surface. Adults are typical blossom visitors, preferring Asteraceae and Apiaceae. Interesting highlight of their biology is the migratory behavior. These migratory insects form swarms, which cross the Alpes towards Southern European areas by using suitable wind conditions, where they finally hibernate and reproduce. The next generation returns the same way back. Not all individuals participate these migratory flights and would try to hibernate in Central Europe. Hibernating individuals are always females, which were fertilized prior to their winter diapause or their migration and which lay their eggs in the subsequent spring or in southern regions during winter. In Germany they only survive in greater numbers in milder winters, which they persist in temperature-stable hideways, such as gaps inside walls or wooden habitats. These specimen can be usually observed early in the year, beginning with March, when visiting blooming flowers. Their numerous very early appearance in mid February 2019 might be due to a very warm summer 2018 and a subsequent very mild winter in north-eastern Germany (Berlin). I have no comparative findings regarding the usual blooming time of the winter aconite and the abundance of drone flies there for Berlin or even this specific urban park. I also don’t know about indications that due to a global warming, as in some migratory birds, less specimens of the fly would migrate and more stay to hibernate here around.

The research station „Randecker Maar“ in the Swabian Jura records changes in migratory flights of birds and insects. They discovered a distinct decline of numbers of migrating drone flies and interpret it as a result of the increasing application of poisonous substances in the agricultural sector. Whether they additionally consider this being due to more individuals hibernating, where they are, based on generally warmer temperatures (global warming) is unknown to me.

 

https://www.instagram.com/p/BuJB6OiFlRi/

Blow fly on blossom of the winter aconite, copyrights Stefan F. Wirth

 

The blow fly Calliphora vicina is a common blossom visitor in early spring and autumn. This fly, typically appearing in human settlements in Europe and the New World, is well adapted for an activity at lower temperatures (more than 13°C). While larvae develop in decomposing organic tissue (such as cadavers of animals), adults feed on nectar and pollen. They additionally incorprate saps from organic material with a strong odor.

C. vicina produces about five generation per year and throughout the year. The flies can even be active in winter, when temperatures reach a suitable level.

 

Other fly species were existant, but I did not determine them.

 

Time of footage and photo recording

 

Video footage and photos were recorded between 16 and 18 February 2019 in the urban park Schillerpark in Berlin.

 

Copyrights: Stefan F. Wirth, Berlin 2019.

Berlin Forest Grunewald and River Havel-Waterside

River Havel

 

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.

 

 

Berlin, December 2018. Copyrights Stefan F. Wirth

Male and female of Histiostoma sachsi and unsuccessful mating with a „stranger“

Mites of the Acariformes vary in very different forms and life-strategies. One taxon of very tiny and soft-skinned mites is named Astigmata. Within them the familiy Histiostomatidae is especially rich of species, most of them surely not yet described or discovered.

 

Modyfied mouthparts and a specific mode of dispersal

 

These mites feed on microorganisms using a complex mouthpart-apparatus with multifunctional abilities. They can be found in habitats, which dry out quickly. When it’s getting too dry, a specific instar of the mites takes a ride on insects or other bigger arthropods for dispersal to a new and fresh habitat ( strategy called Phoresy).

Histiostoma sachsi is one of numerous (often closely related) long haired (in females) species. It was originally in 1957 described from cattle-dung. I found it in compost.

 

Long upper-setation in females and tactile camouflage (mimesis)

 

Adult females are characterized by a long setation on their uppersides. They use them to hold parts of the old nymphal cuticle and soil particles on their backs. This seems to be due to a strategy named mimesis or camouflage. It’s a tactile camouflage as an optical sense in this kind of microhabitats plays almost no role.

 

Normal and unusual copulation position, trial of an interspecific copulation

 

Males mate their females via a dorsal copulation opening and thus need to ride on them. In H. sachsi, that copulation opening is located very close to the hind-edge of the body. That way it is even despite of the camouflage cover accessible. It seems even slightly being elevated out of the body surface in order to surmount adjacent soil particles. This is an adaptation of this particular species. It might share such morphological characters only with very closely related (not yet described) species In other members of genus Histiostoma, the copulation opening is usually more centered related to the hind body.

The copulation position requires that males insert their aedeagus („penis“) into the copulation opening. They additionally use their legs to grasp into the females body. That kind of leg arrangement and thus the whole copulation position can differ from species to species.

This is why copulations between members of different species already fail, because the right copulation setting does not fit, nor does the shape of the aedeagous. Nevertheless the phenomenon of unsuccessful trials for interspecific copulations can sometimes be observed in laboratory cultures. Such a trial is also visible in this video, where a male of Histiostoma feroniarum (also appears in my compost samples regularly) tries to mate a female of H. sachsi. It cannot even almost get in a proper copulation position and seems to hold on to the dorsal camouflage cover of the female. it could only remain in a transverse position related to the female body and thus not get access to the copulation opening, normal would be a longitudinal position with the sameame orientation of female and male.

Adult mites of the family Histiostomatidae (Astigmata) and a „false“ copulation. Copyrights Stefan F. Wirth, Berlin December 2018. Please like my video also at Youtube, in case you like it.

 

Chemical communication and chemo-sensitive leg setation

 

Mites of the Astigmata communicate and find their general orientation due to chemo-sensitive setae, mostly on legs I and II, which are named solenidia. They are even on the magnification level of my footage well visible on the male’s legs. Although a direct body contact is not necessary for a innerspecific communication by chemically interpreting scents produced from mite glands, the observed male in my video repeatedly was seeking for intense body-contacts and obviously „observed“ his conspecific while doing so with its first two legs. This might have intensified the perception of pheromones.

It showed this behavior also, when passing by the „false copulation-pair“ described above. It additionally seemed to invest power in its leg movements as if it would try to remove the „competitor“ on the female, in this case even belonging to another species.

 

Competitive fights between males

 

That mites of the Histiostomatidae can use their strongly sclerotized first legs to fight under each other for an access to a female is known to me from my older observations about the species Histiostoma palustre and Histiostoma feroniarum.

 

Origin of the compost samples

 

The compost samples were collected in SW-Germany (Saarland in October 2018). The footage was recorded in December 2018 in Berlin.

 

Berlin December 2018, copyrights Stefan F. Wirth

Habitat compost: Mite Histiostoma sachsi carries old cuticle and dirt as camouflage

My parents have a compost area in their backyards. I use it as reference habitat for two mite species of the family Histiostomatidae (Astigmata): Since I began my research in 2000, the compost regularly contained Histiostoma feroniarum with its typical male dimorphism. Since summer 2017 another species appears additionally regularly: Histiostoma sachsi. Both species do not appear under the same conditions. While H. feroniarum prefers fresher decaying material, H. sachsi on visibly older decomposed tissue. There mite be even more mites of the Histiostomatidae exist in this complex compost habitat, but under my laboratory conditions, only the two named species were so far successfully reared out of samles always again. Regarding the determination of H. sachsi on a species level, I was more careful in my comments to a former video (June 17), in which I named it Histiostoma cf. sachsi due to doubts about a correct identification. Meanwhile, also due to the morphology of the deutonymph, I determine „my“ compost mite as Histiostoma sachsi Scheucher, 1957. But it is still to emphasize that Scheucher described H. sachsi from cattle dung, not from compost. But generally, both habitats can sometimes share the same inhabitants.

 

Adult females carry their old cuticles and „dirt“ on their backs as tactile comouflage

 

Biologically conspicuous is darkish material, which especially adult females carry on their backs. Unlike males, females posses elongated setae on their backsides. These setae support the holding of material such as old cuticle and soil particles. In slide preparations, this cover usually appears amorphic and contains substrate from the mite’s environment. My video footage indicates that the basis of this cover is a retained old cuticle from the former nymphal instar . That this cannot easily be proven with the light microscope is due to the very soft and fine character of the cuticles in these mites. Remnants might become decomposed by microorganisms after a while.

Compost: the habitat of the mite Histiostoma sachsi Scheucher, 1957 (Acariformes, Astigmata, Histiostomatidae). Copyrights Stefan F. Wirth, please like my video also on youtube, in case you like it.

 

The phoretic dispersal instar, named deutonymph, in mites of the Astigmata controls its body position due to sticky leg endings and suckers on their undersides

 

Deutonymphs of H. sachsi represent one of my resent models to study mite-dispersal behavior. My research focus since a while concerns ultrastructure and function morphology of the deutonympal suckerplates and other structures to attach to insects for dispersal (this dispersal strategy is called phoresie). The anterior front-suckers on the suckerplate of the mite’s underside is extendable and very flexible, not only to find a suitable position on the insect carrier. When falling, the deutonymphs use it to lift their bodies up into a proper position again. Additionally they will try to get hold using „sticky“ lobe-shaped setae on the endings of legs I and II. Both is visible in my footage. The forelegs seem generally to make the first contact, when trying to get on a suitable carrier.

 

Deutonymphs of Histiostoma sachsi take a ride on other mites (Oribatida)

 

The suitable carrier of H. sachsi is unknown to me. Some astigmatid species have even a range of carrier-„hosts“. In my samples, deutonymphs at least attach to other mites, especially to mites of the Oribatida. This is in a very short scene visible in my video too.

 

Copyrights Stefan F. Wirth, Berlin December 2018

Meine Antworten zum Fragebogen der katholischen Zeitschrift „Christ in der Gegenwart“

Die ökumenisch ausgerichtete und überregionale katholische Zeitschrift „Christ in der Gegenwart“ hat einen Fragebogen via Email versandt. Er landete in meinem Spam-Ordner und war auch nicht explizit an meine Person gerichtet. Und dennoch entschied ich mich, die Fragen zu beantworten.

Diese Antworten sollen hier präsentiert werden:

1. Irgendetwas Höheres muss es doch geben.

Nein, ich bin anderer Meinung.
Nicht auszuschließen, aber auch nicht belegt. Die Evolution erklärt alle Vorkommnisse des irdischen Lebens lückenlos.

2. Gott erfährt man eher durch Fühlen, weniger durch Denken.

Nein, ich bin anderer Meinung.
Das würde den Religionsgemeinschaften so passen. Ihre Schäflein bleiben nur dann folgsam und zahlungswillig, wenn man sie dumm hält.

3. Zweifeln gehört zum Glauben.

Ja, das sehe ich so.
Gängige Glaubensdogmen muss man stets bezweifeln!

4. Wenn Gott fehlt, ist alles erlaubt.

Nein, ich bin anderer Meinung.
Dort, wo ein menschengemachter dogmatischer Gott das Sagen hat, ist nicht nur jede Unmenschlichkeit erlaubt, sondern sie ist sogar integraler Bestandteil jeder Glaubensbewegung. Wo ein Menschengott herrscht, herrschen stets auch Diskriminierung, Verleumdung, Hass und Morde.

5. Die Ergebnisse der Natur- und Humanwissenschaften …

… können über Gott keine Aussage treffen.
Seriöse Wissenschaften agieren faktenbasiert. Bei fehlenden Fakten wird keine Aussage getroffen. Es gibt keine wissenschaftlich haltbaren Belege für einen christlichen, einen muslimischen oder buddhistischen Gott.

6. Der zunehmende Wohlstand hat Gott überflüssig gemacht.

Nein, ich bin anderer Meinung.
Das zunehmende Bildungsniveau weltweit und die damit einhergehende zunehmende Individualisierung der Menschen, die Selbstbewusstsein durch Aufklärung erfahren, machen die genannten von Menschen erfundenen Götter überflüssig.

7. Die Kirche sollte sich mehr mit der Frage nach Gott beschäftigen.

Nein, ich bin anderer Meinung.
Die Kirchen dieser Welt sollten sich mehr mit Ethik, Bildung, Toleranz und Menschlichkeit befassen.

8. »Ich bin der Weg und die Wahrheit und das Leben; niemand kommt zum Vater außer durch mich.« (Joh 14,6). Jesus ist der einzige Weg zu Gott.

Nein, ich bin anderer Meinung.
Der historische Jesus aus Nazareth war ein Lehrer für Moral und Toleranz. Anstatt ihn mit der Andichtung albernen Hokuspokus zu verhöhnen, sollte man sich mit seinen Lehren befassen, den Lehren über Moral und Toleranz.

9. Nur mit Gott hat das Leben einen Sinn.

Nein, ich bin anderer Meinung.
Biologisch besteht der Sinn in der Fortpflanzung. Philosophisch sind zahlreiche Zielwerte entwickelbar. Kein dogmatisches Gottesbild wird benötigt.

 

By Stefan F. Wirth

Berlin, Oktober 2018