FSBio-Hannover

In the 1950s it was experimentally established that certain species of tropical fish incessantly emit weak electric discharges, the frequency of which may remain strikingly constant. It has been speculated since then that the fish use the electric field for object detection (Lissmann, 1958).
In 1963, physiologists Akira Watanabe and Kimihisa Takeda observed that individuals of Eigenmannia sp. perform sudden frequency shifts in the presence of electric sources emitting on a similar frequency. An explanation for this behaviour (later named jamming avoidance response - JAR) was suggested only ten years later by neuroethologist Walter Heiligenberg: He was able to show that Eigenmannia sp. lose orientation if their ability to avoid frequency j...

[ Alles lesen ]

Being someone else – the strategy of the Danaid Eggfly (Hypolimnas misippus) optimising chances of survival

Henry W. Bates, a British scientist, was the first to recognise on his journeys between 1849 and 1860 the phenomenon that individuals of the Danaid Eggfly (Hypolimnas missipus) look similar to individuals of another species – the Plain Tiger (Danaus chrysippus). The Plain Tiger is a common butterfly living in Africa. It is inedible and shows a warning colour to discourage predators (Smith, 1973). The Danaid Eggfly is, in contrast, palatable but it shows the same warning colour and behaviour patterns as the Plain Tiger. After reflecting on some possibilities, Bates found an explanation for this phenomenon which is now called
[ Alles lesen ]

Intraspecific communication in bees:
The controversy of distance estimation

As early as the 4th century B.C. the phenomenon of the dance language of honey bees (Apis mellifera) was observed by Aristotle. In the 1940s the zoologist Karl von Frisch discovered that the dance language enables honey bees to inform other foraging bees about the direction and distance of productive food sources by dancing different dances, such as the waggle dance, the sickle dance or the round dance. Later in the 1950s von Frisch hypothesized the energy hypothesis, suggesting that the bee estimates the distance flown by measuring the amount of energy she requires to reach the feedi...

[ Alles lesen ]