Meeting Abstract

38.5  Thursday, Jan. 5  Flexible sex allocation in a group-living simultaneous hermaphrodite HART, Mary K; Univ. of Kentucky, Lexington

Phenotypic plasticity can be helpful for maximizing mating success in variable environments and thus may generate different sex allocation patterns among populations. For Serranus tortugarum, a simultaneously hermaphroditic fish, proportional male allocation (testis mass/total gonad mass) is greater where local density and sperm competition are higher. In the present study, I used reciprocal transplants among four high and low density reefs to test whether adult S. tortugarum show phenotypic flexibility in sex allocation when transplanted from high-density to low-density sites and vice versa. For controls, I included marked residents from each study site in the experiment, and I also tested whether transplants across similar densities would maintain similar sex allocation patterns. After four months, transplants between low density and high density reefs were very similar in proportional male allocation and body sizes to individuals from resident populations at their new reefs. Male allocation was increased through a reduction of relative ovary mass for Low to High density transplants and was decreased through a reduction in relative testis mass for High to Low density transplants. Respective increases in relative testis mass or relative ovary mass with shifts in male allocation, which would indicate the trade-off assumed by theory, were not clearly shown.