MATE CHOICE BY CHEMICAL CUES IN WESTERN REDBACK (PLETHODON VEHICULUM)AND DUNNS (P-DUNNI) SALAMANDERS

Western redback and Dunn's salamanders (Plethodon vehiculum and Pletho don dunni, respectively) can distinguish between potential mates by us ing chemical cues. In laboratory choice tests, adult males of both spe cies showed significant discrimination between chemical cues of gravid females over nongravid females of equal body size. Furthermore, males of both species differentiated the odour of paired gravid females tha t differed by approximate to 5 mm snout-vent length (SVL). Given that clutch size is related to female body size in these species, adult mal es may be able to distinguish between females via cues that signal pot entially high female reproductive success. In choice tests, P. vehicul um females did not discriminate between two relatively large males tha t differed by approximate to 5 mm SVL. However, females of P. vehiculu m did discriminate between two relatively small males that differed by the same amount. Apparently, P. vehiculum females ranked males by bot h absolute and relative body size using chemical cues. This pattern co uld reflect a female preference for large males or that females avoid mating with the smallest males.