Abstract
Male sagebrush crickets, Cyphoderris strepitans, offer an unusual nuptial food gift to females during mating: females chew on the ends of the males' fleshy hind wings and ingest hemolymph seeping from the wounds they inflict. Previous research has shown that once a male has mated, his probability of obtaining an additional copulation is reduced relative to that of a virgin male seeking to secure his first mating, a pattern known as the virgin-male mating advantage. One hypothesis that may explain this phenomenon is that mated males experience an energetically costly immune response via their wounds and therefore may be unable to sustain the costly acoustical signaling needed to attract additional females. To distinguish between the effects of mounting a costly immune response and the costs of producing a spermatophore, we mimicked a nonÂvirgin mating status by injecting virgin males with bacterial lipopolysaccharides, a non-living elicitor of several immune pathways. After they had been treated, males were released in the field and recaptured over the course of the breeding season to monitor their mating success. Contrary to our prediction, LPS injected males did not take longer to secure matings than sham-injected virgin males. However, a companion study revealed that immunochallenged virgin males spent significantly less time calling (as assayed using time-lapse video photography) than shamÂcontrol virgin males. This confirms work in other cricket species showing a decline in mating effort following an immune challenge.