Ethotypic Variation of Prey Recognition in Juvenile Anolis lineatopus (Reptilia: Iguanidae)


Arbeitsgruppe für Verhaltensforschung, Fakultät für Biologie, Ruhr-Universität, Postfach 102148, D-4630 Bochum.


Among prey-naive Anolis lineatopus from Jamaica, individuals reject ants most commonly, crickets less commonly, and waxmoth larvae almost never. This study investigates the individual differences in the mechanism underlying prey perception in two of many ethotypes found, i.e., cricket-rejectors and cricket-acceptors. In one experiment artificially coloured live waxmoth larvae, crickets and ants were presented, in another experiment crickets and waxmoth larvae were moved passively with different speeds. Ethotypes differ in their evaluation of the interaction of prey key stimuli. Cricket-rejectors and cricket-acceptors differ in their responses to both crickets and waxmoth larvae that were either unicoloured yellow or black, but not in their responses to two types of ants of either colouration. Both ethotypes also differ in their preferences for artificially moved crickets and waxmoth larvae as a function of the interaction of prey type and velocity.

In all but two prey items there is interaction in the perceptual pathways concerned. The first presentation in ontogeny of an ant inhibits attack on a cricket presented the next day. Some results suggest that ethotypes differ but gradually in their evaluation of stimuli presented, with cricket-rejectors having a higher threshold for attack. However, other results suggest that cricket-rejectors evaluate certain prey in a way qualitatively different from that of acceptors. At present there is little evidence for an understanding of the ethotypic differences of prey selection at a neural level, probably because neuroethologists have failed to look at individual differences of prey recognition; this failure is discussed in some detail.