biologe

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

Tag: species

Mites, Biodiversity, evolution, species extinction, new species

More Specialists are needed to study our biodiversity: recognizing and describing new species, redescribing known ones, mapping their distribution and understanding their ecological role in an ecosystem.Thus we have to support our children and students to become fascinated by nature.

Also interested laypeople, hobby researchers and nature lovers can contribute to species preservation and nature conservation (and thus climate protection) and encourage their children or relatives to study biology or a similar subject.

Es werden mehr Spezialisten benötigt, um unsere Biodiversität zu studieren: neue Arten zu erkennen und zu beschreiben, schon bekannte Arten neu zu beschreiben, ihre Verbreitung zu kartieren und ihre ökologische Rolle in einem Ökosystem zu verstehen. Daher müssen wir unsere Kinder und Schüler dabei unterstützen, sich für die Natur zu begeistern.

Auch interessierte Laien, Hobbyforscher und Naturfreunde können einen Beitrag zum Arten- und Naturschutz (und damit zum Klimaschutz) leisten und ihre Kinder oder Angehörigen für ein Studium der Biologie oder eines ähnlichen Faches animieren.

© Stefan F. Wirth, Berlin 2022

I provide advices and information about the topics mites (in general, in your house or your company and in a hygiennic context), biodiversity, correlation biodiversity research and climate change, speciation processes, describing new species, species extinction, taxonomy for private people, educational institutions, e.g. schools or university students. Please see my menue item „Angebot biologische Beratung…“

Ich biete Beratung und Informationen zu den Themen Milben (allgemein, in Ihrem Haus oder Ihrem Unternehmen oder im hygienischen Kontext), Biodiversität, Korrelation Biodiversitätsforschung und Klimawandel, Artbildungsprozesse, Beschreibung neuer Arten, Artensterben, Taxonomie, für Privatpersonen, Bildungseinrichtungen, z.B. Schulen, oder Studenten. Bitte beachten Sie meinen Menüpunkt "Angebot biologische Beratung..."

Berlin Forest Grunewald and River Havel-Waterside

River Havel

 

The river Havel has its source in the Mecklenburg Lake Plateau and after 94 km flows in the area of the border between the federal states Brandenburg and Sachsen-Anhalt into the big river Elbe.

Havel runs besides the already mentioned states Brandenburg and Sachsen-Anhalt also through Berlin, the capital city of Germany. On its way, the river passes several bigger and smaller lakes, which serve as water reservoirs, even in hot summers, in which many german rivers and lakes from low water levels.

In its most parts, Havel is navigable, and weirs and locks regulate water levels and water supply.

Historically, Havel since at least 928 of our Western calculation played importent roles as natural border and water route. Through the middle ages up to times of the GDR wetlands as important ecosystems were stepwise drained. In more recent times the protection of unique nature refuges is proceeding. In 2004 for example, the Naturfreunde Deutschlands and the German Fishing Federation elected the Havel area as River Landscape of the year.

In 2005 the Federal Agency for Nature Conservation (BfN) and the Nature Biodiversity Conservation Union (NABU began the land restoration to create refuges for rare bird species , beaver, river lamprey, otters and other animals and plants.

The footage of my video was captured close to the bathing beach area „Lieper Bucht“. Visible are the Havel islands Lindwerder and Schwanenwerder as well as edges of the forest area „Düppeler Forst“.

River Havel and Forest Grunewald in Berlin, quadcopter footage. Copyrights Stefan F. Wirth, December 2018. Please like my video also on youtube, in case you like it.

 

Forest Grunewald

 

Adjacent to the Lieper-Bucht area, the huge urban forest Grunewald extends over 3000 hectare between the Berlin districts Charlottenburg and Zehlendorf.

It was elected as Forest Area of the Year by the Union of German Foresters in 2015. The Grunewald ecologically has a specific mosaic of ecosystems: heathlands, neglected grasslands, dunes, dandpits and marshlands. They all bear a remarkable biodiversity of rare animal and plant species.

Geomorphologically the Grunewald area was formed by galcio-fluvial processess during the Weichselian glaciation , which endet about 11600 years ago. Glacio-fluvial sands cobver the area in layers up to 20 meters and more.

The footage of my video also shows the so called Grunewald Tower. The memorial for the German Emperor  William I was planned in 1897 and finally built up by the architect Franz Schechten. The tower was finally inaugurated in 1899 and renovated between 2007 and 2011.

The footage was captured with a DJI Mavic pro quadcopter in mid December 2018.

 

 

Berlin, December 2018. Copyrights Stefan F. Wirth

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

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

 

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

 

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

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

 

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

 

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

 

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

 

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

 

Copyrights Stefan F. Wirth, Berlin December 2018