Chemical signaling is an important facet of vertebrate communication, and amphibians are no exception. However, very little is known about adult anuran (frog and toad) chemical communication, with the few studies that have investigated chemical sensing in adult anurans documenting species- and sex-biased behavioral responses to chemical cues. Varied life histories and reproductive pressures likely dictate these responses, but to better understand the prevalence and purpose of adult anuran olfaction across species, information on chemical sensing across a large number of species is needed. We investigated sex-biased adult Northern Leopard Frog (Lithobates pipiens) behavioral responses to familiar and unfamiliar conspecific chemical cues to determine the importance of olfaction in conspecific recognition. Our results indicate that adult females respond to conspecific cues, with females spending significantly more time investigating cue vs. control sides of the testing arena. Results for males were equivocal, with males responding much more variably. Comparisons of familiar vs. unfamiliar cues indicate that both sexes tend to spend more time near familiar cues, although this was not statistically significant. Females also responded to unfamiliar, opposite-sex conspecific cues, indicating chemical cues may be involved in mate identification for female Leopard Frogs. Unfamiliar, same-sex conspecific odors did not appear to influence behavior for either sex. Collectively, our results indicate that adult Northern Leopard Frogs utilize chemical sensing for conspecific recognition and further indicate a sex-bias in that sensing, with adult females exhibiting a stronger response than males. Future research should investigate aquatic vs. terrestrial cues and learned vs. innate odors of significance to Northern Leopard Frog adults.
