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Oribatida mites: Fast runners and slow crawlers

Microhabitats often consist of a complexity of organism species. Under suitable conditions, samples can be kept „alive“ for months and even for years by regularly adding moisture and organic tissue, in case of my sample of this footage: patato pieces.

 

 

Mites of the Oribatida and their different ways of locomotion. Copyrights: Stefan F. Wirth, Berlin April 2019. Please give the video a like on youtube too.

 

Soil samples from island Norderney

 

This soil sample was collected in summer 2018 on the North Sea island Usedom during my participation at the „Geo Tag der Natur“. It contained several specimens of the predatory chilopode Lithobius sp. and pieces of rotting wood, moss and forestground, everything collected under rotting treetrunks and tree branches. The samples additionally contained the carabid beetle Pterosticus cf. niger and ants of genus Lasius. Samples were collected in a small forest area with wetland aspects. The soil quality was rather moist.

 

Astigmatid mites

 

I later added potato pieces and regularly some water droplets to the sample with still living big arthropods/ insects. After some weeks, specimens of the astigmatid mite Acodyledon cf. schmitzi developed on dryer areas of the potato pieces. These mites were presumably phoretic associates of the carabid beetles. They died out after several months, after the sample had dried out a little bit and may be due to changes of the room temperature during winter time.

 

Oribatida

 

Now, almost a year later, the micro habitat is inhabited by mites of the Oribatida in greater numbers of specimens of at least three species: Nothrus sp. (genus not yet clarified), Nothrus palustris (already found for the first time shortly after the sample collection) and a species of Phthiracarida.

 

Locomotion and biodiversity

 

Purpose of the short film is to show different organisms, cultured after about a year in this sample: mites, nematodes, collembolans and microorganisms, fungae and bacteria. Of the bigger arthropods/insects, only one Lithobius species survived until now.  Also the diversity of ways of locomotion in different oribatid species is emphasized: There are slow crawlers (Nothrus) and fast runners (Phthiracarida).

 

Berlin, April 2019, Copyrights Stefan F. Wirth

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Agriculture, natural countryside and stream pasture landscape north of Berlin

Berlin as a green city

 

 

Berlin, lake Köppchensee, March 2019. Copyrights Stefan F. Wirth.

 

Berlin is an unusually green metropolis. Besides numerous urban park landscapes and the huge forest area Grunewald, there is a unique countryside north of Berlin, including the area of the old village Lübars, being surrounded by numerous fields (Lübarser Felder) and a stream pasture landscape, named Tegeler Fließ, with bog meadows.

 

 

Nature sites Lübarser Felder, Arkenberge, Schönerlinder Teiche in 4K, copyrights Stefan F. Wirth. Please also like my video on Youtube.

 

Mounts Arkenberge and pondlandscape Schönerlinder Teiche

 

In the northeast, around the urban village Blankenfelde, the currently highest elevation of Berlin can be found, the Arkenberge. Originally, they represented a chain of smaller mounts as natural remnants of the Weichselian glacier. One of these mounts is especially conspicuous and is acually prepared to become accessible for people and forms with a height of 122 m over NHN the highest mountain of Berlin. It represents despite of its natural origin a rubble landfill site, which was formed beginning in 1984.
Adjacent to the Arkenberge, several wetland areas attract nature enthusiasts for hiking tours: the pond landscape „Schönerlinder Teiche“ (Brandenburg) and the lake Kiessee Arkenberge.

 

Mount Arkenberge with Kiessee Arkenberge, Berlin March 2019. Copyrights Stefan F. Wirth.

 

Mount Arkenberge, Berlin February/ March 2019. Copyrights Stefan F. Wirth

 

Eurasian blue tit at Schönerlinder Teiche (Wandlitz), February/ March 2019. Copyrights Stefan F. Wirth.

 

Ponds Schönerlinder Teiche (Wandlitz, Brandenburg), February/ March 2019. Copyrights Stefan F. Wirth.

 

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.

 

Lake Köppchensee as part of the Tegeler Fließ lowland, March 2019. Copyrights Stefan F. Wirth.

 

Video footage and photos

 

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.

 

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.

 

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.

Mite Histiostoma sachsi (Astigmata): Juvenile dispersal instar deutonymph and its orientation behavior

Some animals live in environments, where there is (almost) no light available. It makes no sense to see in the dark, but it is important for a specimen to know, where it actually is, where it is going to, whether there is enough food and what the conspecifics are doing. Predators need to be recognized in time, and a sexual partner must be found. There is also need for an efficient communication between specimens of a species. How can all this be performed by mites of the Astigmata, which usually live inside decomposing soil habitats in a more or less permanent darkness?

 

Olfactory sense organs in mites of the Histiostomatidae

 

Histiostoma sachsi (Histiostomatidae, Astigmata) is such a mite, living inside cow dung or compost. It might have a rudimentary ability for a light perception, but has not visible or functional eyes. It cannot produce any sounds. It can only feel and smell. Seemingly very limited abilities, but the contrary is fact: Due to evolution this mite is perfectly adapted to its life-style. It can feel objects by touching on them using its body setation (= body hairs). And it smells by means of very specialized body hairs, which are called solenidia and appear in different types, shapes and functions. These mites don’t smell on the level of us humans, which would be very insufficient. If at all, it should be compared with a dog. I am always fascinated when seeing blind dogs and how perfectly they can interact with their environment, despite their handicap. That’s may be how the efficiency of olfactory perception abilities of such a mite must be imagined. They do not only perceive scent particles from other animals, plants and soil components. Even olfactory signals from their conspecifics will be correctly and differentiatedly interpreted. And that not only marginally.  Olfactory signals represent indeed the major mode of their intraspecific communication.

 

Chemical communication of mites of the Histiostomatidae

 

Communication always requires contributions from both sides, a signal and an answer. These mites smell the signal of a conspecific using their solenidia, and they answer by the secretion of biochemical components. For these purposes, they possess a huge and complex gland system located on the upperside of their backs. Volatile excretions aggregate inside a big and rounded reservoir and finally leak to the outside via a pore, called oilgland opening. These gland systems are located symmetrically on both sides, each with one reservoir and one pore.

The meaning of the sent volatile message simply depends on the composition of the correspondingbiochemical components. Even diffferent stereochemical configurations of the same molecule can have different meanings. Citral for instance is a major component and has in different stereoisomers different functions. Such cummunicative volatile signals are usually named pheromones. And mites of the Histiostomatidae can indeed produce different kinds of pheromnes via the same gland system. Aggregation pheromones inform specimens about a suitable place to stay together with their conspecifics, for example due to a sufficient amount of food resources. Alarm pheromones solicit mites nearby to flee from an unpleasant situation. Sexual pheromones attract adult partners to each other in order to perform the mating procedure. But the gland secretions can even more. As allomones, they communicate with specimens of other species. They function as defenses against predators or other dangerous cohabitants.

 

Deutonymphs need to find a carrier for dispersal

 

Another form of communicative interspecific interactions is performed by a specific juvenile instar, the deutonymph. It looks morphologically quite different from all other instars (heteromorphic situation), does not need or possess a functional mouth, has a thicker cuticle as protection against drying out and a complex sucker organ on its underside in order to attach itself to an insect or another bigger arthropod. Deutonymphs of the astigmatid mites search for bigger carrier-arthropods to get carried from one habitat to another (dispersal strategy  is calledphoresy). While doing so, they again use their specifically modified leg setation (hairs) on the first pairs of legs to perceive scents for the detection of a suitable and passing by carrier. Basically it is still unknown, whether the term „communication“ is indeed appropriate in this context as we don’t know yet about a mutual interaction between deutonymphs and their carriers, before the phoretic ride begins.

 

 

Olfactory orientation of the deutonymph of Histiostoma sachsi, copyrights Stefan F. Wirth, February 2019.

 

Specific way of walking in deutonymphs

 

In detail, different kinds of behaviors can be observed in deutonymphs, when searching a carrier. The detailed behavioral patterns in this context can slightly differ between even closer related species. Deutonymphs of Histiostoma sachsi as all deutonymphs show a characteristic mode of walking, in which especially the first pair of legs plays an important role. During each step, performed by four pairs of legs, the first legs are lifted up much higher than all other hind legs. While doing so, they slightly tremble up and down. A behavior that mostly supports a better basic orientation inside a „jungle-„micro-landscape, being filled up with soil particles and decomposing plant tissues. But what H. sachsi deutonymphs additionally need in order to find their carriers is repeatedly to rest between the walking activities. Thus the first legs, which normally are still walking legs, are made free and that way available for the perception of carrier-scent-components only. These  namely are the legs that bear the highest densiy of solenidia.

 

Two different behavioral modes for an efficient orientation towards a carrier

 

Two different modes of resting with olfactory searching activities could be observed: In periodic intervals the deutonymph attached to the ground by using its sucking structures. They were then more or less laying on their entire undersides with only their forebodies slightly lifted up. By alternating moving the first legs up and down, olfactory information could be perceived from all directions without having the own body as a barrier to backwards. To improve its orientation situation, the deutonymph additionally turned on its own axis around, being stabilized by its sucking structures, which are flexible enough to follow these movements. When the deutonymph intended to continue its walk, it first needed to detach from the ground, which happened via muscle contractions that caused an abrupt detachment of the corresponding suckers. But main aim of the deutonymph is to find an elevated place, where the probability of a passing by carrier is especially high and from where a bigger insect (or other arthropod) can easier be ascended. There the second behavioral mode was performed. The deutonymph only fixed the edge of its hind body to the ground, again using the suckers on its underside, which are located close to this edge. This time the entire mite body stood in an upright position. The first legs again „waved“ alternating up and down and could under these especially elevated conditions even perceive scents from bigger distances. By occasionally slightly and alternating turning their upright bodies to both sides, olfactory information could be easier detected from all directions.

 

Carrier of H. sachsi still unknown

 

The frequency of such movements in mites increases typically as closer a suitable carrier approaches. But this was not yet observed or documented for Histiostoma sachsi. Its carrier inside the compost substrate is still unknown, which is why I so far could’t perform corresponding experiments. The species‘ describer, Scheucher (1957), found her mite specimens in cow dung and also didn’t identify the corresponding carriers there.

The observations presented in my video are part of my research project about morphologies and behaviors of deutonymphs in the Histiostomatidae.

 

Berlin, February 2019. All copyrights Stefan F. Wirth.

 

Arapaima gigas, einer der größten Süßwasserfische – doch was sind Fische eigentlich?

Sie sind beeindruckende Fische, nicht nur aufgrund ihrer Größe. Und doch kennen die meisten Menschen sie nur aus den Aquarienhäusern zoologischer Gärten. Arapaima gigas wird mindestens zwei Meter lang und erreicht in Ausnahmefällen sogar Längen von über drei Metern. Beheimatet ist die Art im Bereich des Amazonas-Beckens und ist in Peru, Brasilien und Guyana verbreitet.

 

Arapaima gigas, einer der größten bekannten Süßwasserfische aus dem Amazonas-Gebiet

 

Arapaima ist ein Räuber. Erwachsene Fische ernähren sich von anderen Fischen sowie Tieren in vergleichbarer Größe, wie zum Beispiel auch kleineren Säugern. Besonders auffällig sind die kräftig gestalteten großen Schuppen, die den Körper der Tiere umschließen. Sie dienen unter anderem als mechanischer Schutz gegen Angriffe durch Feinde. So können sie beispielsweise den Attacken der im selben Lebensraum beheimateten Piranhas, die zwar wesentlich kleiner sind, aber bekanntlich empfindliche Beißwerkzeuge besitzen, wirkungsvoll widerstehen. Das schützt Arapaima freilich nicht vor seinem größten Feind, dem Menschen. Er ist ein beliebter Speisefisch, der durch massenhafte Bejagung in seinem Bestand immer wieder gefährdet wird.

Arapaima gigas wird häufig als größter Süßwasserfisch der Welt bezeichnet. Dies basiert jedoch auf Übertreibungen. In Wahrheit befindet er sich in der Größenordnung des Europäischen Welses, dem größten europäischen Süßwasserfisch.

 

„Fische“ ist keine spezielle systematische Gruppierung

 

Ich verwendete bislang stets unkommentiert den Begriff „Fisch“. Was sind Fische eigentlich?Welche sogenannte Fische kennt man noch? Wie verhält es sich beispielsweise mit dem Bullenhai, der über drei Meter lang werden kann und neben marinen Habitaten auch im Süßwasser auftreten kann. Kann er als Gigant des Süßwassers mit dem Arapaima, dem Gigant aus dem Amazonas verglichen werden? Nach evolutionsbiologisch-systematischen (=phylogenetisch) Gesichtspunkten kann er das nicht. Der Begriff „Fisch“ bezeichnet nämlich keine spezielle, systematisch in sich geschlossene Gruppe. Stattdessen haben wir es mit einem deskriptiven Begriff zu tun, der alle Tiere umfasst, die in ihrer Gestalt ganz grundsätzlich eine gewisse Ähnlichkeit mit dem Goldfisch aufweisen.

Wenn wir außer Acht lassen, dass auch „Tintenfische“ und „Walfische“ nach demselben Muster benannt wurden, die bekanntlich zu den Mollusken und Säugetieren gehören, weist die Fischgestalt zumindest in den meisten Fällen auf eine irgendwie gestaltete Verwandtschaft hin. Jedoch sind Haie und Arapaima dennoch nicht sonderlich nahe miteinander verwandt.

 

Arapaima gigas im Aquarium des Zoos Berlin, ein gigantischer Süßwasserfisch, der regelmäßig atmosphärische Luft an der Wasseroberfläche aufnehmen muss. Copyrights Stefan F. Wirth

 

Bei den „Fischen“ handelt es sich nämlich um eine sogenannte paraphyletische Gruppe. Das heißt, sie umschließt zwar eine ihnen allen gemeinsame Stammart, jedoch keineswegs alle dazu gehörigen Tochtergruppen. Dazu würden nämlich auch alle Landwirbeltiere gehören. Eine vergleichbare paraphyletische Gruppe stellen beispielsweise die „Reptilien“ dar, zu denen Eidechsen/Schlangen, Schildkröten, Krokodile und alle Dinosaurier gehören. Da die Vögel aus den Dinosauriern hervorgingen, jedoch nicht zu den „Reptilien“ gezählt werden, haben wir es unter dieser Bezeichnung wieder mit einer Stammart und nur einem Teil aller Tochtergruppen zu tun, die allerdings im Stammbaum der Tiere nebeneinander stehen und daher näher miteinander verwandt sind, so wie auch bei den „Fischen“.

Im Falle der „Fische“ (paraphyletische Gruppen werden häufig in Anführungszeichen gesetzt) verhält es sich so, dass die verschiedenen als Fische bezeichneten Gruppen neben nur ihnen eigenen Merkmalen auch unterschiedliche Merkmale aufweisen, die auf eine Ahnenlinie hin zu den Wirbeltieren zurückgeführt werden müssen. Was unterscheidet also Knorpelfische (zum Beispiel Haie) und Strahlenflosser (Actinopterygii = echte Fische) voneinander? Eine Frage, die so in der modernen Systematik, die stets nach Gemeinsamkeiten sucht, eigentlich nicht gestellt wird. Richtiger ist es, zu fragen: Welche Merkmale teilen die Knorpelfische mit den Landwirbeltieren (z. B. knöcherner Schädel, Kiefer) und welche die Strahlenflosser (z.B. Lunge). Wenn man dennoch über Unterschiede sprechen möchte, ist festzustellen, dass Knorpelfische noch keine Lunge, die mit jener der Landwirbeltiere homolog ist, besitzen, Strahlenflosser aber schon. Die Lunge ist also auf der Ahnenlinie der Knorpelfische hin zu den Strahlenflossern evolviert. Anders als die „Fische“ sind die Strahlenflosser, die ich hier auch als echte Fische bezeichne, sehr wohl eine geschlossene systematische Einheit (=Monophylum), die auf Merkmale einer gemeinsamen Stammart zurückgeführt werden kann, die nur dieser Gruppe eigen sind. Ein Beispiel ist die namengebende Gestalt der Flossen, die durch Flossenstrahlen durchsetzt sind.

 

Zuerst gab es Lungen, aus denen Schwimmblasen evolvierten

 

Die Strahlenflosser (Actinopterygii), zu denen neben unzähligen Arten auch Arapaima gehört, besitzen also in der Tat ursprünglich paarige Lungen als Respirationsorgane. Diese sind demzufolge nicht erst vor dem Abzweig der Lungenfische entstanden, die als nächste Verwandte der Landwirbeltiere gelten. Die dortige Neuerung betrifft, anders als der Name Lungenfisch vermuten lässt, die Evolution eines Lungenkreislaufs, den es bei urtümlichen „Fischen“ mit Lunge noch nicht gegeben hat.

Aber besitzen echte Fische (Actinopteryii) nicht Schwimmblasen und atmen ausschließlich durch Kiemen? Mitnichten. Ursprüngliche Vertreter der echten Fische werden beispielsweise durch die Flösselhechte (Polypteriformes) representiert, die paarige sackförmige Lungen besitzen und neben der Kiemenatmung daher auch atmosphärische Luft veratmen können. Diese beeindruckenden Tiere können sich mithilfe ihrer Flossen nicht nur an Land fortbewegen, sondern lassen sich (es gibt Experimente an Senegal-Flösselhechten) auch unter vorwiegend terrestrischen Bedingungen in Terrarien halten.

Erst innerhalb der echten Fische ist die Schwimmblase entstanden, die sich durch Evolution aus den Lungen heraus bildete. Die fachgerechte Beschreibung lautet daher: Lunge und Schwimmblase sind einander homologe Organe. Innerhalb der Actinopterygii gibt es einen evolutiven Trend, demzufolge die Schwimmblase bei urtümlicheren Vertretern (noch) der Atmung dient, bei evolutiv weiter abgeleiteten Vertretern hingegen nur noch die Funktion der Austarierung im Wasser übernimmt.

Allerdings ist es innerhalb der echten Fische oftmals schwierig zu entschlüsseln und noch immer Gegenstand phylogenetischer Studien, ob die Lungenfunktion einer Schwimmblase einen Hinweis auf Urtümlichkeit darstellt, oder ob sekundär aus einer Schwimmblase mit Tarierfunktion erneut ein Atmungsorgan entstanden ist. In der Evolutionsbiologie werden im Übrigen unabhängige Entwicklungsschritte stets als Konvergenzen bezeichnet.

 

Arapaima gigas veratmet mithilfe seiner Schwimmblase atmosphärische Luft

 

Auch Arapaima gigas ist ein Luftatmer, der auf den Einsatz seines zusätzlichen Atmungsorgans in Form einer Schwimmblase sogar angewiesen ist. Er ist ein obligater Schwimmblasenatmer, der atmosphärische Luft an der Wasseroberfläche mithilfe seiner Mundöffnung aufnehmen muss. Dies wird als Anpassung an den häufig sauerstoffarmen Lebensraum der Tiere interpretiert, die sich häufig in Überflutungszonen des Amazonasbeckens aufhalten, wo wenig im Wasser gelöster Sauerstoff zur Verfügung steht. Der Literatur zufolge muss Arapaima gigas alle fünf bis fünfzehn Minuten die Wasseroberfläche aufsuchen, um dort mit seinem oberständigen Maul Luft einzuschnappen.

 

Berlin, Februar 2019, 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

„Me-too“-debate and documentation-film „Leaving Neverland“ – is medieval sentencing without any trial the newest step into our modern future of social interacting?

When a person was illegally harmed, then I expect him or her as the victim of a crime in most imaginable cases being immediately aware of something having being undoubtfully wrong, independent of the victim’s age. There might be cases and reasons, such as for example shame that can prevent an official accusation made by the victim, for a while.

But remembering serious sexual crimes only decades later, exactly, when the career is unstable enough to need a major attention, then doubts should be advised.

 

Documentary „Leaving Neverland“, a witch-hunt?

 

The 2019 documentary film „Leaving Neverland“ by the British director and producer Dan Reed is actually capturing a major attention after it was presented at the Sundance Film Festival on January 25 in 2019. The co-production between the UK Channel 4 and the US Home Box Office (HBO), presents the alleged stories of two men: Jimmy Safechuck, who performed as child in a Pepsi commercial with Michael Jackson and Wade Robson, a today dancer and choreographer. They both claim to have been over years repeatedly sexually abused by the King of Pop.

 

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Singer and performer Michael Jackson again accused of paedophilia, a modern witch-hunt? Photo-rights: German Wikipedia

 

Michael Jackson won all trials against accusations of paedophilia. No indications towards sexual crimes remained. Let’s say except of the unusual and for some people’s eyes bizarre life-style and look of the singer and performer, who very obviously simply liked children in legal and natural way. In his most famous music video, „Thriller“, he appeared as a monster. Obviously the monster that so many conservative, intolerant and uninspired people want to see, even today. The modern trends of an exuberant extreme-feminism contributes to these monster-desires. Some of these hardliners generally fight for an anti-male-agenda. All males are suddenly monsters with uncontrollable sexual pressures, which they permanently practise against everything and everybody. And if they want to imagine a superlative of all these monsters everywhere, then Michael Jackson fulfills enough clichés to act as a convincing monster, even years after his death.

 

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Aerial photography of Jackson’s „Neverland-Ranch“, photo-rights: German Wikipedia

 

The reaction of the „US Weekly“-journalist Mara Reinstein is absolutely according of very modern ideas of justice, it’s all about, what you feel, not what you know. Best is, when it’s against males and somehow in context with sexual accusations. That’s why she informed the world via her Twitter-account, how sick she felt in her stomach after watching the premiere of part 1 of the documentary, and how very credible the victims were coming off. I wish Mrs. Reinstein a very speedy recovery, and I think she is a very great role model, when it’s all about credibility.

 

#MeeToo, a modern (male) witch-hunt?

 

Since mid October 2017 a special hashtag overwhelmed the world: #MeToo. Suddenly countless famous male film-makers and artists became victims of sexual-abuse-accusations, using the same patterns mentioned above. But is the term „victim“ always correct in that context? Yes it is. Does that mean that all accusations were false accusations? Unfortunately not. But all modern legal systems (at least in occidental countries) require a trial, which judges against the accused. Judgements in the run-up to a court hearing or even without any court hearing at all are illegal, and in the worst case make a perpetrator as culprit indeed to a victim.

 

Character assassination and bullying!

 

When normal people and not a court judge somebody’s alleged crimes with existential consequences for that person, which are irreversible even after a later non-guilty-sentencing by a court, then this needs to be named: character assassination! It is a moral offence, which is also often called bullying, an offence, which is mostly not considered liable to prosecution, incredibly!

 

Witch-hunt in the Middle-Ages

 

From the biological point of view, humans are not as social as they are supposed to be. Almost all human skills that differ us from other Great Ape species evolved in smaller populations. Homo sapiens is until today not perfectly adapted in living in extreme big and complexe communities. Specific behavioral characters, evolved in prehistoric times, appear under modern conditions even more distinctive. These are laziness, egoism and unscrupulousness.

 

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Malleus Maleficarum, „Hammer of Witches“, treatise on witchcraft by Henricus Institoris, photo-rights: German Wikipedia

 

Dangerous and sinister characters from the medieval period even towards the early modern times, exactly knew, how to make use of these unfavourable human behavioral tendencies. When for example the German churchman Henricus Institoris, better known as inquisitor Heinrich Kramer, in the late 15th century began to sow hatred between German families, friendships, neighbors and cohabitants, then he just needed a quite simple strategy to successfully perform his hysteric witch-hunt: When he arrived in a city or a village, he asked for denunciations. And he got stacks of them, what easy way it was to get rid of a competitor, an unbeloved family member or an uncooperative rich elderly lady. To officially accuse them as witchcraft was all they needed to do in order to eliminate their own people. When the real switch is pressed, humans can unfortunately still easily forget all mercy,  solidarity and humanity.

We don’t need witch-hunts in our 21th century!

 

Berlin, January 2019. Copyrights Stefan F. Wirth

 

 

 

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

Kardinal Brandmüller und seine Heuchelei über vorgebliche Heuchelei

Missbrauchsskandale in erheblichem Ausmaße erschüttern bereits seit geraumer Zeit die Katholische Kirche. Seit geraumer Zeit? Im Grunde muss man doch annehmen, dass es in Wahrheit um einen Zeitraum geht, der die gesamte Dauer der Existenz dieser Kirche umfasst, doch dazu später mehr.

Missbrauch an Minderjährigen im Deutschland der vergangenen 68 Jahre

Papst Franziskus hat sich mehrfach deutlich gegen Täter in den eigenen Reihen ausgesprochen, womöglich aber erst, als Leugnung oder Ignoranz aufgrund offen gelegter Fakten nicht mehr möglich waren. Einer Studie aus dem letzten Jahr konnte entnommen werden, dass im Zeitraum zwischen 1946 und 2014 in Deutschland insgesamt 1670 katholische Geistliche sexuellen Missbrauch an 3677 Minderjährigen betrieben, wobei es sich bei den Opfern zumeist um heranwachsende Männer handelte.

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Papst Franziskus, für viele ein Reformverweigerer, für manch hochbetagten Kleriker jedoch unzumutbar modern, Quelle Foto: Wikipedia

Der deutsche Kardinal Walter Brandmüller und seine Bemühung zur Verniedlichung sexueller Straftaten durch Mitarbeiter der Kirche

Der fast 90-jährige deutsche Kardinal Walter Brandmüller nimmt dies zum Anlass, eine gegen die Kirchenmoral sprechende Statistik ins vermeintlich richtige Licht zu rücken. „Was in der Kirche an Missbrauch passiert ist, ist nichts anderes, als was in der Gesellschaft überhaupt geschieht“, so seine Stellungnahme. Sexueller Missbrauch sei kein spezifisch katholisches Phänomen. Außerdem sei darauf hinzuweisen, dass „80 Prozent der Missbrauchsfälle“ an männlichen Jugendlichen begangen worden seien, womit er den direkten Zusammenhang zwischen Homosexualität und dem Missbrauch an heranwachsenden Männern konstruiert.

Kardinal Brandmüller gilt als erzkonservativ und zählt zu den offenen Kritikern von Papst Franziskus, der aus Sicht vieler Intellektueller zu wenige Reformen durchsetzt, in den Augen von Hardlinern wie Brandmüller jedoch mit Neuerungen allzu sehr über die Stränge schlägt. So hat er zusammen mit dem ebenfalls konservativen Joachim Meisner (inzw. verstorben) einen offenen Kritik-Brief an den Papst verfasst, der als „Dubia-Brief“ bezeichnet wird und vor allem die Öffnung der Kirche gegenüber wieder verheirateten Geschiedenen kritisierte.

Die Katholische Kirche als Refugium

In seinen Einlassungen zu den Missbrauchsfällen, die die Kirche erschüttern, hat Kardinal Brandmüller keineswegs grundsätzlich Unrecht. Sexueller Missbrauch findet auch außerhalb von Institutionen der katholischen Kirche statt. Außerdem legen sexuelle Straftaten männlicher Kleriker an männlichen Jugendlichen in der Tat einen homosexuellen Zusammenhang nahe. Doch bleibt uns Herr Brandmüller eine Erklärung dafür schuldig, welche Institution in Deutschland außer der Katholischen Kirche eine Statistik vorweisen kann, die es im Verlaufe von nur 68 Jahren auf ganze 3677 Missbrauchsfälle an Minderjährigen gebracht hat. Wohlgemerkt die Dunkelziffer nicht nachgewiesener Straftaten außer Acht gelassen!

Klar ist, dass die Neigung zu sexuellen Straftaten unter hetero-, bi- und homosexuellen Männern generell gleich verteilt ist. Nicht ganz so klar ist allerdings, warum sich homoerotisch motivierte Straftaten in beeindruckender Dichte nun ausgerechnet in den Reihen der Katholischen Kirche häufen. Hierzu äußert sich der betagte Kardinal ebenfalls nicht. Legt eine Betrachtung der gesamten Kirchengeschichte denn nicht nahe, dass es sich bei dieser Institution schon seit jeher um ein Refugium für Menschen mit ungewöhnlichen sexuellen Vorlieben handelte? Ist ja klar, mag mancher jetzt argumentieren, Schwule neigen nun einmal zur Perversion. Aber mitnichten!! Lediglich ist es so, dass die strukturelle Organisation der Kirche gezielt schon immer diejenigen erotischen Abweichler aus einem großen Pool der Bevölkerung herausfilterte, die zudem zufällig schwul oder bisexuell veranlagt waren. Denn wer sonst fühlt sich in Gemeinschaften wohl, die fast ausschließlich aus Männern zusammengesetzt sind? Doch warum das besondere Potential für sexuelle Straftaten? Weil die Kirche zum einen legale erotische Verbindungen verbietet, Stichwort Zölibat, und weil es wenige vergleichbare Großorganisationen gibt, in denen persönliche Willkür, Machtmissbrauch und Korruption eine ähnlich lange und vor allem erfolgreiche Tradition haben, geradezu eine Einladung also an alle, die nach Unmoralischem und striktem Eigennutz streben.

Kritik wird von Kardinal Brandmüller harsch zurückgewiesen. „Da benimmt sich die Gesellschaft ziemlich heuchlerisch“, äußert er im Zusammenhang mit den stattlichen Missbrauchszahlen durch Kleriker. Ist es nicht heuchlerisch, dort Heuchelei zu unterstellen, wo berechtigte Kritik vorgebracht wird, die eigentlich nur eine Reaktion moralisch vertretbar macht: die Bitte um Vergebung begangener zahlreicher und schwerer Sünden sowie die Gelobigung der Besserung? Zumindest in diesem Punkt ist der eigentlich selbst viel zu rückständige Papst Franziskus in der Tat in seinem Handeln weit voraus!

Wünschenswerte und notwendige Reformen

Ich bin kein Fan der Katholischen Kirche, wahrlich nicht. Sie hat seitdem sie existiert Leid über die Menschheit gebracht, hat gemordet, Kriege geführt und gefoltert, sich gegen die Aufklärung und selbstbestimmte Denker gestellt. Es ist ihr nach all den Jahrhunderten endlich eine Erkenntnis der Werte zu wünschen, für die ihr Namensgeber ursprünglich eingestanden ist: Nächstenliebe, Toleranz und Moral! Zwar muss man bei aller kritischen Haltung auch anerkennen, dass es genau diese Kirche war, die sich zwar stets bemühte, unerwünschtes Wissen zu bekämpfen, andererseits jedoch durch Vertreter der eigenen Reihen auch erheblich zu Erkenntnisgewinn beigetragen hat, nicht zuletzt auch dadurch, die Literatur der letzten Jahrtausende in hervorragend organisierten Bibliotheken für die Nachwelt zu erhalten. Auch die Entwicklungen in der Kunstgeschichte wurden maßgeblich durch die Kirche mit beeinflusst. Da jedoch all dies heute längst durch andere Einrichtungen übernommen wird, kommt die katholische Kirche nicht mehr umhin, sich vollständig umzustrukturieren, um vergangene Fehler zu vermeiden. Es muss das Prinzip Vorrang finden: weniger Dogmatismus, stattdessen unbegrenzte geistige Freiheit und vor allem mehr soziale Verantwortung. Wird das nicht ernst genug genommen, wird diese Kirche keinen Platz mehr in der Zukunft haben, die uns bevorsteht!

Berlin, Januar 2018, 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