RESPONSES TO MULTIPLE CHEMICAL CUES BY THE CRAYFISH ORCONECTES VIRILIS

conectes virilis to nalural chemical stimuli presented both one at a lime and in combinations were recorded in the laboratory. Following the introduction of predator (snapping turtle) odours, individuals decreased the rate of non-locomolury movements compared to control levels. The addition of food odour resulted in an increase in movement as well as postural changes. When both signals were presented simultaneously, the level of food-elicited movements was reduced and the extent of inhibition of food-related responses depended upon the relative inlensily of the two types of input. The behavioural effect of predator odour introduction lasled about two hours. When alarm odour and food odour were presented simultaneously, movements were reduced even more strongly than with the predator odour-food odour combination. Presentation of two signals associated with danger (alarm and predator odours) resulted in a significantly greater reduction of food odour-induced movement than for either danger signal by itself.