Meeting Abstract
106.4 Tuesday, Jan. 7 09:15 Do females gain direct benefits from immune-boosting ejaculates in the Texas field cricket? WORTHINGTON, A.M.*; KELLY, C.D.; Iowa State University; University of Quebec, Montreal aworthin@iastate.edu
Promiscuity is ubiquitous in nature and females often mate more than is necessary to ensure reproductive success. Although mating multiple times generally increases female fecundity and offspring quality, it can impose significant costs to survival. Mate searching, courtship, and copulation can result in physical injuries and drastically increase rates of parasitism, predation, and disease, thereby reducing overall female fitness. In crickets, however, multiply mated females have greater longevity relative to once-mated females. The functional mechanism underlying this mating-related increase in longevity is not known, but some evidence suggests that mating boosts female immunity. We used the Texas field cricket, Gryllus texensis, to test whether mated females receive direct benefits from males in the form of immune-boosting ejaculatory compounds or whether copulation increases female investment in immunity. In our laboratory-controlled experiments, females were assigned to one of four treatments where they experienced: 1) physical contact with a male; 2) male courtship but no ejaculate; 3) received a partial ejaculate from a castrated male containing only the accessory fluids; or 4) received an intact ejaculate containing sperm and accessory fluids. Two days after mating, females were subjected to host resistance tests comprising an LD50 dose of the bacteria Serratia marcescens. We predict that if males provide females with immune-boosting ejaculatory products, then females that receive an ejaculate will exhibit increased disease resistance. Alternatively, if mating causes females to invest more in immunity, then physical contact or male courtship will elevate female disease resistance.
