Behavioural responses to alarm odours in indigenous and non-indigenous crayfish species: a case study from Western Australia.

The assertion that invasive species show higher plasticity in the use of information than indigenous ones was analysed in an indigenous crayfish Cherax tenuimanus (marron) and the non-indigenous C. albidus (yabby) in temperate Western Australia. In the laboratory, both species displayed a measurable change in their behaviour when presented with odours produced by food and by damaged conspecifics. They also reacted to heterospecific cues, possibly because similar to70 years of sympatry had led the two species to learn each other's alarm signals. However, this may be explained as a case of phylogenetic inertia and/or may be related to similar mechanisms of chemical detection. Yabbies displayed shorter reaction times and clearer changes in their body posture to heterospecific odours than did marron, supporting the view that invasive crayfish make faster and more appropriate use of information than those species they are displacing.