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Kategorie: Berlin

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

 

Different wing colors in a harlequin ladybeetle specimen

The ladybeetle Harmonia axyridis is naturally distributed over eastern Asia, but was imported to the United States already at the beginning of the 20th century as pest control. At first, there was no population development in the open fields. These were at first reported from Louisiana in 1988. In 2001 the first free living specimens were for Europe discovered in Belgium. Since then the beetle distributed over several European countries, such as France, entire Germany or Switzerland.

 

Variations of Harmonia axyridis

 

The beetle is well known for its great form variations. Worldwide more than 200 different color pattern forms of thorax and elytrae are described. They are distinctly shaped and maintain in this shape and arrangement of pattern. But four forms dominate within natural populations. Speaking about the elytrae (not the thorax patterns), the reddish form with dark spots, as visible in my film, is one of them.

These distinct different forms must be named a polymorphism and are based on genetic information as well as on environmental conditions, such as temperature, humidity and light intensitivity. According to that even the term polyphenism might be adequate.

 

 

 

 

Transcription factor pannier responsible for color pattern polymorphism

 

According to the work of M. Gautier et al. (the genomic basis of color pattern polymorphism  in the harlequin ladybird, Current biology, 28, 20), the transcription factor pannier is responsible for the genetically based control of this polymorphism. They discovered that different pannier alleles determine the color pattern in the different known forms. The authors furthermore report that pannier was never found before to play a keyfactor role in the pigmentation of insects.

 

Ladybeetle species on a meadow in Berlin

 

The specimen in my footage was discovered on an urban meadow in the park area „Nordhafen“ in Berlin. It’s a meadow in autumn predominantly consisting of lucerne and clover, sorrel and yellow field cress. Different ladybeetle species could be in greater numbers found there between September and October 2019. The sevenspot-ladybird, the adonis ladybird (Hippodamia variegata) and most abundant the harlquin ladybird in all its developmental stages.

 

Asymmetrical wing colors and possible explications

 

 

Harlequin beetle specimen from Berlin with asymmetrically colored wings, copyrights Stefan F. Wirth, please like my video also on Youtube

 

The most conspicuous character of „my“ harlequin ladybird specimen was its distinct asymmetrically colored wings (elytrae). One side reddish with black spots, the other side brownish with black spots. During my research about such asymmetries in ladybirds, I didn’t find recent studies, which distinctly focussed on that topic. H. E. Roy et al. reported in their book „ladybirds“ (original version 1989, revised version 2013) about the existance of such differently colored wings in the same specimen. They emphasized that the phenominon was not studied in detail, but assumed different factors being eventually responsible for such a development of a beetle individual: 1) disruption of pigment production, 2) mitotic mutation in early development, 3) environmental conditions, eventually influencing the colors of an originally normal developed young adult (exposed for longer time to different light intensities etc.). The latter might in the case of „my“ specimen being an indeed possible factor, as it is clearly visible that also the brownish wing has at its edges some of the reddish pigments.

 

 

Filming/ photography conditions

 

The beetles was filmed and photographed under artificial conditions in a soil and grass-set in my video lab. There, mites of the Gamasina (Parasitiformes, evtl. mostly Laelapidae) were common. They interestingly showed a phoretic behavior by quickly climbing onto the wings of that ladybeetle. They obviously recognized it as a suitable carrier to new habitats. I assume ladybeetles in the field not being of much attraction for phoretic dispersal, based on their life-cycles and preferred habitats.

 

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

Complex and modified mouthparts in Histiostomatidae mites

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.

 

Diphyletic origin of mites

 

Mites are not longer just mites. The former two clades of mites, Parasitiformes and Acariformes, originally considered as sister taxa, were in the modern systematics reconstructed to be diphyletic. That means, there was no commor ancestor, from which only those two clades derived.  There is no close relationship between them,each clade is most closely related to different groups of arachnids.  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).

 

big male 2 Saarland compost

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 and astigmatid mites, there evolved a tendency towards miniaturization. Mites of the Astigmata are usually much smaller than one mm. Correspondingly the cuticle becam 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

 

Rollei Digital Camera

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. I presented such video footage in one of my former mite videos. To get off from the underground requires a jerky upward movement of the whole mouthpart apparatus (also visible in that older video). As I observed different developmental stages of different species, I could conclude that on a smooth surface with randomly dispersed food supply, regular stops and mouthpart-sucking-activities are seemingly a most common behavior of histiostomatids, while a straight forward walking behavior with the gnathosoma permanently touching the ground in order to push microorganism covers to the body`s front side only than occured, when food supply was uniformly dispersed (under artificial experimental conditions) under uniform moisture conditions.

 

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 feroniarum feeding from a substrate mount inside its original habitat. Fixation with hexamethyldisilazane, SEM photography, 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.

 

Fig. 2

Mite Histiostoma feroniarum feeding from substrate mounts inside its original habitat (A-F). Rounded particles might represent yeast bodies. D = distal chelicera endings (digitus fixus), holding food particles, fixation with hexamethyldisilazane, SEM photography, copyrights Stefan F. Wirth

 

Berlin, September 2019

 

Copyrights Stefan F. Wirth

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

Eudicella colmanti – Mating behavior of a colorful beetle

Rose chafers represent a group of colorful beetles, which taxonomically belong to the Scarabaeidae and thus are relatives of famous beetles such as Scarabaeus sacer, well known for rolling dung into balls and for being an important symbol for creation and the rising sun in the ancient Egyptian world. Even the stag beetles are more distant relatives of rose chafers.

 

Colorful and active during daytime

 

Unlike some related beetle clades, rose chafers are usually active during the day. This is also indicated by their very colorful bodies. Colors in insects can have different functions, but they usually all are optical signals, which require a visibility in the sun light. Greenish colors are common in rose chafer species and might have optical inner specific signal functions, but also might support an optical camouflage. This would also make sense in the preferred habitats of the adult beetles, which usually feed on softer parts of blossoms and on their pollen. But they also feed on fruits, whereby mostly liquids are incorporated as the chewing mouthparts are not very well developed.

 

Tropical rose chafer Eudicella colmanti during its copulation behavior, 4K videography, copyrights Stefan F. Wirth.

 

Tropical rose chafers from African countries

 

About 3000 species of rose chafers are known, of which most inhabit the tropical zones. The about 20 species of the genus Eudicella are more or less restricted to the African continent.

Eudicella colmanti is native to Gabun, Kamerun and Kongo, thus a species with a main distribution in Central Africa. But E. colmanti is like other species of this genus worldwide often kept in terraria, although species like E. smithi are more common inhabitants of this kind of artificial habitats. They all can be more or less easily reared.

 

Specific flying mode and copulation behavior

 

This is why I was able to study behavioral characters in detail. And rose chafers indeed show interesting behaviors. They for example perform a unique way of flying. It is a specific character of rose chafers (a so called apomorphy) that they fly with closed fore wings, which cannot be opened as in other beetles.

I documented in my video the mating behavior of a beetle couple. Interestingly this was not too difficult, although both genders can, when separated from each other, react to disturbances with a high agility.

 

Almost permanent copulation activities

 

But in the copulatory position, they accepted to be removed from their terrarium to the filming set and even stayed in position, when they were enlighted from different positions with very bright light beams. Please note the the female, which I observed regularly actively searching for a position underneath the male (behavior not clearly visible in my footage). But it also conspicuously never stopped feeding (on an apple) during the copulatory process (very well visible in my footage), obviously to obtain enough nutrients for the production of eggs. A copulation in my couple is not a unique event, but is repeated regularly and can take hours.

 

Phoretic mites

 

Both genders carried bigger numbers of mites. These were phoretic deutonymphs of the taxon Astigmata (Acariformes, Acaridae). As never determined the mite species, as it was not clear, whether it represented a natural associate of these tropical beetles, or whether it was a species native to Germany, which for example was carried into the terrarium via Drosophila flies.

Copyrights Stefan F. Wirth, Berlin March 2017/ February 2019

Berlin forest Grunewald – former gravelpit area, type location for the mite Histiostoma palustre

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.

 

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Right modified leg of a male of Histiostoma palustre. Copyrights Stefan F. Wirth, 2002/ 2019

 

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Modified leg of a H. palustre male in closed position. Copyrights Stefan F. Wirth, Berlin 2002/ 2019

 

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Underside of a H. palustre male with modified leg. Copyrights Stefan F. Wirth 2002/ 2019

 

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Asymmetry: male of H. palustre with only the right leg modified. Copyrights Stefan F. Wirth 2002/ 2019

 

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Asymmetry: male of H. palustre with only the left leg modified. Copyrights Stefan F. Wirth 2002/ 2019

 

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Copulation of a Histiostoma palustre male with both-sided modified legs. Copyrights Stefan F. Wirth, Berlin 2002/ 2019

 

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Details of a copulation with a modified male, copyrights Stefan F. Wirth, 2002/2019

 

 

Berlin, January 2019. Copyrights Stefan F. Wirth

Months passing, but where has all the life gone?

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

 

 

Berlin, December 2018. Copyrights Stefan F. Wirth

 

 

 

 

 

Phoretic Mites waiting on Ant Pupae

Greater numbers of pupae from a nest of the myrmecine ant Myrmica rudinodis are attached by phoretic mites, which wait for these pupae to hatch. They would then attach the newly developed ants to be carried around and dispersed this way. They this way had already occupied their later ants before, namely during their pupal stage, one could call this phenomen „pupa-guarding“. In my samples, I discovered two species of mites performing this pupa guarding behavior. Most abundant were deutonymphs of the mite Forcellinia wasmanni (Astigmata). But also individuals of a mite species of the Gamasina were repeatedly discovered sitting on pupae, where they were hiding between head, ventrum and limbs of the pupa. They even seemed to defend their pupae, when they felt disturbed, e.g. by my filming activities.

 

Ant pupa guarding by mitees, looking for a carrier for dispersal

 

These pupa guarding-findings concerning this ant and with these corresponding mite species might be new to science (so far I didn’t found literature indications) and thus need to be studied closer in the future in order to understand the whole context of behaviors. In the footage, two types of pupae are visible, pupae of the winged alates and those of workers. Mites generally prefered both, but especially the deutonymphs of Forcellinia wasmanni seemed to appear more often on the pupae of later workers. Most pupae had at least one deutonymph attached, rarely, there were found up to four individuals. This is different to what could be found on older workers. They on their ventral side can have 4-6 deutonymphs. Many workers seem to be covered with the deutonymphs, but I didn’t check more workers until now, so I can’t say, how many were without mites. It is unknown, how deutonymphs come to the pupae, whether they simply leave older workers for the pupa-guarding or whether they were waiting in the soil for the pupae to arrive (due to the brood caring activitoes of the ants).

Mite-Life inside an ant nest. Copyrights Stefan F. Wirth 2015/18

 

Astigmatid mite with a strict relationship to ants

 

The mite Forcellinia wasmanni is known to be strictly associated with ants (e.g. Türk & Türk 1957). It is clear that attaching young female alates would secure the dispersial of the mite into a new ant nest. It is not clear, which function the transport via ant workers can have. But Türk & Türk (1957) mention that the free living instars of Forcellinia wasmanni would feed on dead ants. Such a kind of microhabitat for the development is not unique in astigmatid mites. Some species within the Astigmata are known to have such preferences for decaying cadavers, but are then feeding on microorganisms, which grow on these (insect) cadavers. Ant workers might be ideal to carry mite deutonymphs to new cadavers, where they would leave and develop. Ants generally have a very well developed hygienic behavior. This guarantees the mites to get access to cadavers regularly. I do not know any other video footage, showing living deutonymphs attached to their carriers on such a magnification level as visible in this film. The original footage of these deutonymphs is much longer.

 

Morphology and behavior of the dislersal-instar, the so called „deutonymph“

 

The function of the proterosoma (dorsal shield of the forebody) is acting as a flexible structure, protecting the mouthpart-area (non-functional in deutonymphs) and the fore-legs, but being very motile and being easily pushed backwards (under the following hyterosoma-shield), when the mite lifts up from the surface of the ant pupa. I cannot state much more concerning the second mite, found on pupae, which is a species of the Gamasina. I discovered this phenomenon only on three of my pupae. Ant nests represent complex communities of organisms, to which fungae, other insects, mites and nematodes can belong. The samples visible in this film were collected in July 2015 on the German island Usedom inside a forest area between the villages Zinnowitz and Karlshagen. The ant nest was quite small. An ant hill was not visible.

 

Complexity of life in ant nests

 

The complexity of life within ant nests is a result of evolution. I am an enemy of creationistic movements, including all modern faces of creationism. Creationism stimulates carelessness und illiteracy in the believing people.

 

 

Berlin August 2015/ December 2018, copyrights Stefan F. Wirth