The use of conspecific and heterospecific alarm cues by virile crayfish (Orconectes virilis) from an exotic population

The successful establishment of a population of introduced animals is dependent upon a number of variables, including the ability to respond adaptively to novel stimuli indicating predation risk. Previous studies have suggested that exotic crayfish have an advantage over native species, in that the former respond to alarm cues released from both injured conspecifics and injured heterospecifics and the latter typically respond only to injured conspecifics. This pattern could be a result of learning in the new environment or a predisposition of certain species to respond to a broader range of alarm stimuli. We tested between these possibilities using individuals from an exotic population of the virile crayfish (Orconectes virilis). The crayfish responded similarly to alarm cues from conspecifics, sympatric heterospecifics, and novel heterospecifics. The results suggest that these animals enter a new habitat with the ability to respond adaptively to a wide range of predation risk cues, but more work is needed before this hypothesis can be accepted conclusively.