Meeting Abstract

P3.126  Friday, Jan. 6  Context-dependent mate choice in female spadefoot toad hybrids SCHMIDT, E.M.*; PFENNIG, K.S.; Univ. of North Carolina, Chapel Hill; Univ. of North Carolina, Chapel Hill

Two species of spadefoot toads, Spea multiplicata and S. bombifrons, potentially hybridize where they co-occur in the southwestern USA. Hybrids between the two species are viable; however, hybrid males are potentially sterile and females may be only partially fecund. Nevertheless, hybridization can be beneficial for S. bombifrons females in some environments. Indeed, hybrid tadpoles develop more quickly than pure S. bombifrons tadpoles, and are therefore more likely to metamorphose and escape shallow ponds before they dry. Consequently, S. bombifrons females prefer heterospecifics when in shallow, but not deep, ponds. This facultative preference for heterospecifics is condition-dependent: females in poor condition are more likely to prefer heterospecifics, presumably because females in poor condition produce more slowly developing offspring. How such a behavior evolves depends, in part, on the expression of mating behaviors in hybrids. We therefore examined the mate preferences of hybrid Spea females. Females were tested for their preferences for S. bombifrons or S. multiplicata male calls, and for each of these calls versus a synthesized hybrid call, in conditions mimicking both deep and shallow ponds. Each test was repeated four times to test for individual consistency. Preliminary results show that hybrid females significantly prefer hybrid calls over S. multiplicata calls in deep water, but not in shallow water. Moreover, our results suggest that switches in hybrid female preference between deep and shallow water are condition-dependent. These results suggest that hybrid Spea adjust their mate preferences based on environmental context and their own body condition in a manner similar to S. bombifrons. This has important implications for the study of mate choice variation and the consequences of hybridization.