Kapitel: Gyrinus, Orectochilus, Gyrinus Marinus, Aulonogyrus
Concinnus, Gyrinus Minutus, Gyrinus Urinator, Gyrinus Colymbus,
Orectochilus Villosus. Aus Wikipedia. Nicht dargestellt. Auszug:
The whirligig beetles are a family (Gyrinidae) of water beetles
that normally live on the surface of the water. They get their
common name from their habit of swimming rapidly in circles when
alarmed, and are also notable for their divided eyes which can see
both above and below water. They are also known for their grouping
behavior, a survival mechanism which helps them to avoid predation.
Their places in the group are thought to be determined by a number
of factors, including hunger, sex, species, water temperature, age,
parasite level and stress level. Research being done on their
behavior serves as a model to study the significance of chemical
defense in relation to their position in the group, which relates
to such fields as nanotechnology because the beetle's motion
provides insight into the way in which groups of robots might
coordinate movements. Specifically, the beetles make behavioral
trade-offs which lead them to different group positions. For
example, relatively hungry beetles go to the outside of a group,
where there is more food but higher risk of predators. Males are
also more likely to be found on the outside of groups (although
grouping is unrelated to mating behavior in this family).
Individuals swimming against the flow of water in a stream
incorporate the needs of drafting into these group positioning
decisions. Drafting is when animals swim behind others to take
advantage of forward-moving drafts. The determination of
forward/backward positioning within a group has been found to be a
complex function relating to the: speed of the water, the sex of
the beetle, and the type of predator (bird or fish) most recently
observed by a beetle. They have a bubble of air trapped underneath
their abdomens which allows them to dive...http:
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