ALLOZYME AND ADVERTISEMENT CALL VARIATION IN THE TUNGARA FROG, PHYSALAEMUS-PUSTULOSUS

We analyzed variation in advertisement calls and allozymes in 30 popul ations along a 5000-km transect throughout most of the range of the tu ngara frog, Physalaemus pustulosus. All 12 call variables measured sho w significant differences among populations despite the importance of the advertisement call in species recognition. Some call variables exh ibited clinal variation, whereas most others differed between the two major allozyme groups that have invaded Panama at different times, per haps 4-4.5 million yr apart. Call variables that primarily affect disc rimination among conspecifics tended to exhibit greater variation than call variables that are crucial for species recognition. The proximat e mechanism of production underlying a call variable, however, is a be tter predictor of its variation. Contrary to predictions of some sexua l selection models, carl Variation exhibits predictable patterns of ge ographical variation, although a substantial portion of variation amon g populations is not explained by geographic position. Although allozy mes, calls, and geography usually covary, closer populations can have more similar calls independent of allozyme similarity.