Invasive species of crayfish use a broader range of predation-risk cues than native species.

The responses of invasive and native species of crayfish to conspecific and heterospecific alarm odors were recorded in the laboratory. Individuals of the North American invasive Procambarus clarkii responded just as strongly to odors from crushed Austropotamobius pallipes as they did to crushed conspecifics. The North American invasive Orconectes limosus also respond as strongly to P. clarkii odor as to consepcific odor. The native Italian species A. pallipes responded more strongly to conspecific alarm than to heterospecific alarm from P. clarkii. The pattern of invasive species of crayfish using a broader range of danger signals than displaced native appears to be robustus.