Integration of multiple predator cues by the crayfish Orconectes propinquus

We examined the responses of individual crayfish (O. propinquus) to cues as sociated with predation risk in the laboratory. We presented visual and tac tile cues either alone or in combination with conspecific alarm odour. The addition of alarm odour resulted in crayfish responding to a visual cue at a greater distance and with a stronger response in terms of distance retrea ted. Similarly, the frequency of response and the magnitude of the response s shown to a tactile cue were higher when alarm odour was added, but only a t night. During the day, the addition of alarm odour did not affect the res ponses shown to tactile input. We then presented a dilution series of alarm odour solutions (100, 50, 10 and 1% strength) in combination with the visu al stimulus. There were no differences in response parameters with chemical cues of different strength. We discuss the response patterns observed with regard to the ecology of O. propinguus compared with related species of cr ayfish. (C) 2001 The Association for the Study of Animal Behaviour.