Paternal effects on juvenile growth and survival in spring peepers (Hyla crucifer)

Abstract

In 1986 and 1987 we crossed severalHyla crucifer females to males that obtained mates in nature and to large and small body sized males that did not do so. Offspring resulting from these crosses were raised as pairs of juveniles in 1986, or in isolation in 1987 to assess sire effects on juvenile growth and survival in a competitive and a non-competitive context. When raised as part of a pair of juveniles, individuals sired by natural mates had lower growth rates than their fullsibs raised alone. The reduction in growth was of a similar magnitude whether the cohabiting juvenile was sired by a large or small bachelor. When raised together, individuals sired by natural mates had higher growth rates (indicative of competitive superiority) than their halfsibs sired by large bachelor males, but competed as equals with the progeny of small bachelor males. Progeny of large bachelors competed with progeny of small bachelors as equals. When raised individually in 1987, juveniles sired by natural mates had lower growth rates than their halfsibs sired by bachelor males. Paternal size or mating status had marginally non-significant effects on juvenile survival in 1986 and no effect in 1987. The larger individual in a pair was more likely to survive in 1986. In neither year was juvenile growth rate correlated with prior growth rate as a larva. These experiments suggest that the mating system can affect the distribution of juvenile growth rates (and possible survival rates), and thereby have important fitness consequences long after pair formation. These effects are, however, inconsistent either among sets of individual males or among juvenile environments.