Detection of conspecific chemical cues by juvenile amphibians during initial orientation and movement away from the breeding pond may be useful in habitat selection. Through a five-year study of habitat preference at a single pond, we have found that orientation patterns of juvenile amphibians are non-random within years but vary across years. Because the surrounding environment has not changed substantially through the course of study, use of habitat specific orientation cues seems unlikely. We hypothesize that chemical cues from other conspecific juveniles may affect initial orientation. To test our hypothesis, choice tests and Y-maze tests were completed using juvenile American toads (Bufo americanus). In choice tests, we tested an individual’s preference for 1) their own scent versus another juvenile’s scent and 2) their own scent versus no scent over a three hour period.
Results/Conclusions
In the first 30 minutes of the choice tests, juvenile American toads demonstrated non-significant tendencies towards another’s scent over own scent (P=0.11) and own over no scent (P=0.13). For the choice test between own and another’s scent, this trend was stronger within the first 15 minutes of testing (P=0.056). Despite the lack of statistical significance, if these trends are biologically significant, juveniles may orient according to available scents early during the testing period, but switch to random movements when it becomes clear to juveniles that extended linear movement in the initial direction of orientation is impossible. For Y-maze tests, juveniles were tested for their ability to follow a linear path previously traveled by another juvenile. However, the frequency with which juveniles chose the previously traveled path did not differ from random (P>0.50). Although results suggest that significant preferences for conspecific chemical cues may not exist in a laboratory setting, the use of chemical cues is still a possible mode of orientation for juvenile amphibians. Our study is effectively a pilot study, and in the future, we hope to refine our methods and expand our study to different species to more accurately represent the role of chemical cues in orientation behavior.
