SENSORY CUES FOR CONSPECIFIC ASSOCIATIONS IN AQUATIC SAN MARCOS SALAMANDERS

The mode and effectiveness of signals greatly depends on habitat characteristics and the activity patterns of a species. Visual cues frequently are involved in social interactions, although their effectiveness can be reduced with nocturnal species or in habitats with limited visibility. The combination of multiple signals, such as chemical and visual cues, can increase the accuracy and efficacy of communication in these systems. Association preferences of male and female Eurycea nana were examined by allowing individuals to choose between members of both sexes based on (1) chemical signals, (2) visual signals, and (3) chemical and visual signals. Both sexes showed stronger associations with the chemical signals and combined chemical and visual signals of the opposite sex than with visual cues alone. The simultaneous inclusion of both chemical and visual signals did not increase male or female responses suggesting that chemosensory communication is sufficient for individuals of this aquatic species to distinguish between the sexes at close range. Additionally, the finding that females as well as males exhibit sexual discrimination suggests that both sexes seek out potential mates, a phenomenon rarely seen in salamanders.