Socializing makes thick-skinned individuals: on the density of epidermal alarm substance cells in cyprinid fish, the crucian carp (Carassius carassius).

Published version of an article in the journal: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. Also available on SpringerLink: http://dx.doi.org/10.1007/s00359-010-0550-4 In cyprinid fish, density of epidermal club cells (i.e. alarm substance cells) has been found to vary between lakes with different predator fauna. Because predators can be labelled with chemical cues from prey, we questioned if club cell density could be controlled indirectly by predators releasing prey cues. In particular, we suspected a possible feedback mechanism between chemical alarm signals and their cellular source. We raised crucian carp singly and in groups of four.…