What do hermit crabs eat in captivity

Hermit crabs weigh up their fighting behavior when attacked by conspecifics. If it seems favorable to them, they behave contrary to their actual patterns of action, as researchers working with Robert Elwood from the Royal University of Belfast have discovered.

The scientists equipped smaller hermit crabs (Pagurus bernhardus) with sandy shells of the blunt periwinkle (Littorina obtusata), a control group received clean housing. Then the researchers let the crabs compete against each other. Normally the animals try to defend their own housing and to conquer those of other conspecifics if they appear more desirable.

During the fighting, however, all hermit crabs with sandy shells tried to get rid of their dirty shells. If the crabs attacked with the dirty shells, they acted much more aggressively than their conspecifics in the control group. On the other hand, if they were in the defender's scooter, they often refrained from hiding their small size from larger attackers.

Probably the defensive hermit crabs hoped to be able to take over the snail shell of their opponent after his victory - if he should actually change his shell. Compared to their rivals, the snails with the sandy shells had one piece of information ahead of them: for their conspecifics it was not understandable that the crabs lived in dirty shells. The fact that their rivals did not know about the dirty shells made it happen Pagurus bernhardusThe scientists write that it can be used specifically. The investigation thus provides another example of the effects of unequal background information in combat operations. (may)

This article is contained in Spectrum - Die Woche, October 3rd, 2007