Resource Availability Drives Mating Role Selection in a Simultaneous Hermaphrodite Aplysia californica

In simultaneous hermaphrodites, a clear conflict exists between sperm donor and sperm recipient roles, and how such conflict is mediated remains up for debate. This study observed and recorded mating role selection as a function of resource availability in the simultaneous hermaphrodite Aplysia californica. When food was plentiful, animals assumed both sperm donor and recipient roles at relatively even frequency. However, when half of the mating pairs were placed on restricted diets, food-limited animals assumed the sperm donor role at significantly (P < 0.05) greater frequency than their ad libitum partners; nevertheless, the frequency of successful mating events remained the same. The mass and frequency of eggs laid were also significantly (P > 0.05) correlated with parental food intake. These results demonstrate how mating strategies can change within a mating season, as a result of shifting environmental conditions, and call for a diverse framework to address these issues in simultaneous hermaphroditic mating systems.