Chemical detection of conspecifics in the crayfishProcambarus clarkii: Role of antennules.

Tests with female crayfish (Procambarus clarkii) confirm that conspecifics can be detected chemically. The subjects were more attentive in the presence of water from a stranger's tank than in the presence of water from their own tank. Animals with intact antennules performed this discrimination best, but animals with one intact inner ramus and one intact outer ramus also clearly responded. Conspecific chemical discrimination after loss of both inner or both outer rami was weak (trial 2) or absent (trial 1). The relevance of this outcome to previous conflicting reports on the use of antennules in sex and species discrimination in crayfish is discussed.