We use a combination of microsatellite marker analysis and mate-choice behavior experiments to assess patterns of reproductive isolation of the túngara frog Physalaemus pustulosus along a 550-km transect of 25 populations in Costa Rica and Panama. Earlier studies using allozymes and mitochondrial DNA defined two genetic groups of túngara frogs, one ranging from Mexico to northern Costa Rica (northern group), the second ranging from Panama to northern South America (southern group). Our more fine-scale survey also shows that the northern and southern túngara frogs are genetically different and geographically separated by a gap in the distribution in central Pacific Costa Rica. Genetic differences among populations are highly correlated with geographic distances. Temporal call parameters differed among populations as well as between genetic groups. Differences in calls were explained better by geographic distance than by genetic distance. Phonotaxis experiments showed that females preferred calls of males from their own populations over calls of males from other populations in about two-thirds to three-fourths of the contrasts tested. In mating experiments, females and males from the same group and females from the north with males from the south produced nests and tadpoles. In contrast, females from the south did not produce nests or tadpoles with males from the north. Thus, northern and southern túngara frogs have diverged both genetically and bioacoustically. There is evidence for some prezygotic isolation due to differences in mate recognition and fertilization success, but such isolation is hardly complete. Our results support the general observation that significant differences in sexual signals are often not correlated with strong genetic differentiation.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 60 • No. 8