Genetic variation for larval anuran (Scaphiopus couchii) development time in an uncertain environment

Abstract

Couch's spadefoot toads breed in ponds of uncertain duration. Larvae exhibit considerable variation in growth, size at metamorphosis and development time. Phenotypic differences in development time may dramatically affect survivorship. Additive genetic variance was detected for development time, but not for any other trait. Some variation in early growth was attributed to maternal effects; maternal effects, however, were not apparent for size at metamorphosis or development time. Nonadditive genetic effects were not statistically significant for any trait, but the nonsignificance of these effects must be interpreted cautiously, as the sample of females was relatively small and the mating design used is not very effective for detecting interactions. Genetic variation in development time in this population is most likely maintained by variability in the direction of selection as a consequence of variation in pond duration. -from Author