biologe

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

Tag: females

Locomotion behavior of Schizomida (Arachnida)

They look without magnification more like very motile and fast running ants or very tiny grasshoppers than like arachnids. But they indeed represent relatives of the web spiders and scorpions: Schizomida, a clade of whip scorpions. They are the sister taxon of Thelyphonida, the rather well known „big whip scorpions“, which are often kept as pets in terraria around the world. Schizomida are only rarely filmed in a higher resolution quality, which is due to their small size and their almost invisibility due to their semi-transparent cuticle and their very fast way of walking or even jumping. They are additionally difficult to be filmed as they strictly avoid all lights and tend to dry out quickly, when they cannot hide themselves by time in a slightly moist substrate.

 

Closeups of behaviors of a Schizomid species from a greenhouse in Germany. Copyrights Stefan F. Wirth

 

Schizomida in Greenhouses

 

Schizomids represent mostly tropical or subtropical organisms. But some species are regularly dispersed into greenhouses around the world. The filmed species might be Stenochrus portoricensis, but was not systematically studied in detail so far. As all known species, which appear in greenhouses, also S. portoricensis reproduces (apart from their original habitats) parthenogenetically with females producing females without mating procedures (thelytoky). I never found males so far.

 

 S. portoricensis: native to subtropical Zones

 

The specimens, which I kept since months in a small terrarium, were collected in autumn 2016 at the famous fun and wellness bath „Tropical Islands“ South of Berlin. There they are a natural part of the world’s biggest indoor rainforest. The species S. portoricensis is originally native to Florida, Mexico, Cuba, Nicaragua, Porto Rico and other localities in similar tropical zones. These microscopical tiny organisms are predators and do not harm human beings at all. According to the available organisms in a suitable size in my terrarium, they might feed on the numerous collembolans and/or mites. Especially mites of the Gamasina appear in greater numbers in my substrate, which represents the original substrate from the greenhouse. I enriched this substrate regularly by smaller pieces of fruits or vegetables to stimulate the growth of microorganisms. I keep them at room temperature (about 20°C) and with not too much moisture. I do not know, whether they reproduced within these months, but the specimens of my recent video footage represent all sub-adults.

 

Film set and topic locomotion

 

Focus of my film is to present the different ways of locomotion, cleaning behaviors and burrowing activities of these fascinating animals. During the filming procedure, I used two cold-light-lamps for a suitable illumination and an ILCE-6300 (internal 4K mode), connected to a stereomicroscope and a lightmicroscope (with uplight).

 

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

Hamadryas Baboon Behaviors

They belong to the same phylogenetic clade of Primates than Homo sapiens. Hamadryas baboons (Papio hamadryas) miss our ability for a complex facial expression (unlike chimpanzees for example, our sister-group), but we can nevertheless read about their moods, when we look into their faces. When we watch boboons, then many of their behaviors and interactions look familiar to us.

The phylogenetic tree of the Primates (Apes), to which we humans belong, clearly prooves that we derived from old world monkeys due to evolution. Hamadryas baboons live in East Africa and there are well adapted in surviving in a dry environment. They are omnivorous feeders and prefer plants and seeds, but can also hunt smaller mammals or reptiles. This species of baboos is characterized by a specific sexual dimorphism, which represents an apomorphy for P. hamadryas.

Hamadryas baboons and aspects of their social behaviors. Copyrights: Stefan F. Wirth

 

Males have almost the double size of females, and their fur is silver-white and covered by a conspicuous mantle. The social system is rather complex. But it begins with a very simple society structure, which is called the „one-male unit“, which can be named synonymically a „harem“. Such a unit consists of one dominant male, several females and their infants. Several one-male units can cooperate with each other.

That way a more complicated social hierarchy within the populations is formed. I had primatology courses in Berlin, when I was a student and always had a special fascination for these baboons. That’s why I decided to record this footage in the Berlin Zoologischer Garten.

May 2016/ November 2018. Copyrights Stefan F. Wirth.