Density‐Dependent Growth and Fecundity in the Paedomorphic Salamander Ambystoma Talpoideum

The growth responses of larval salamanders reared under various environmental conditions were examined in relationship to adult fitness in a factorial experiment. Larvae were reared in artificial pond to measure simultaneously the effects of pond—drying regime, food level, and initial density on growth and fecundity of paedomorphic Ambystoma talpoideum. Pond—drying regime, initial density, and the drying regime x food level interaction affected early larval growth. Early larval growth was highly positively correlated with adult body size. Drying regime, food level, and initial density all significantly affected the number of ova paedomorphic females contained. The number of ova was positively correlated with body size. Removing the effects of snout—vent length by analysis of covariance revealed that variation in the number of ova was largely (84%) due to the effects of body size. Larvae grew fastest, attained the largest body size, and contained the most ova in constant water, high food, and low—density ponds. The results of this experiment demonstrate a direct relationship between phenotypic variation generated in the larval stage and adult fitness. These results suggest that the larval environment strongly affects the fecundity of adult salamanders at first reproduction and imply that behaviors influencing the selection of oviposition sites by parents can dramatically affect the ultimate reproductive fitness of the next generation.