Maternal Effects on Offspring Quality in Poeciliid Fishes

SYNOPSIS. We evaluated the effects of maternal environment onoffspring size and composition in three species of poeciliidfishes. We chose food availability as the environmental factorfor study. Mature females were assigned to either high or lowfood for an interval of time, then randomly reassigned to highor low food, with the restriction that there be equal numbersin each of four treatments: high-high, high-low, lowhigh, andlow-low food availability. The three species chosen for studydiffer in the pattern of maternal provisioning. Poecilia reticulataand Priapichthys festae mothers provide all resources necessaryfor development as yolk, prior to fertilization. In contrast,Heterandria formosa mothers continue to provision the youngthroughout development. These species also differ in whetheror not they have superfetation, or the ability to carry multiplebroods of young in different stages of development. P. reticulatadoes not have superfetation while the other two species do.We were interested in whether the pattern of maternal provisioningor superfetation influenced the maternal effect. The two lecithotrophicspecies responded to low food by producing larger young withgreater fat reserves. H. formosa, the matrotrophic species,responded to low food by producing smaller young. We proposethat the production of large young in the face of low food availabilitymight represent adaptive plasticity; matrotrophy might representa constraint that prevents such an adaptive response. Superfetationhad no impact on this maternal effect.