Hydration benefits to courtship feeding in crickets

Abstract

The spermatophore transferred by male decorated crickets (Gryllodes sigillatus) at mating includes a large gelatinous spermatophylax that the female consumes after copulation. Although previous studies have shown that G. sigillatus females gain no nutritional bene¢ts from consuming food gifts, there may be other bene¢ts to their consumption. We examined potential hydration bene¢ts to females by experimentally manipulating both the availability of water and the number of food gifts that females consumed, and by measuring their e¡ect on female ¢tness. Analysis of the number of nymphs produced by females revealed a signi¢cant interaction between the number of spermatophylaxes consumed and water availability. When spermatophylaxes were not provided, females given water ad libitum produced signi¢cantly more nymphs than females subjected to water stress. Female longevity was signi¢cantly a¡ected by water availability, with an increase in the availability of water corresponding to a signi¢cant increase in female longevity. These data suggest that female G. sigillatus accrue ¢tness bene¢ts by consuming spermatophylaxes when alternative sources of water are unavailable. In addition, females appear to allocate water contained in spermatophylaxes towards reproduction as opposed to survival.

Sensory exploitation as an evolutionary origin to nuptial food gifts in insects

“…The absence of a nutritional bene¢t of spermatophylax consumption does not, of course, preclude the existence of other kinds of bene¢ts; indeed Ivy et al (1999) recently showed that female Gryllodes sigillatus subject to water stress secure signi¢cant hydration bene¢ts through nuptial feeding. Notwithstanding the existence of these or other undetected nutritional bene¢ts to nuptial food gifts, they cannot alone account for the evolution of post-copulatory female choice in gift-giving species.…”

Free amino acids as phagostimulants in cricket nuptial gifts: support for the ‘Candymaker’ hypothesis

“…In support of this, the number of spermatophylaces consumed by female G. sigillatus has been found to have no effect on the number of eggs produced ( Will & Sakaluk 1994;Kusaya & Sato 1998), although Kusayo & Sato (1998) did find that the rate of oviposition appeared to be increased by spermatophylax consumption in this species. Spermatophylax amino acids might, however, be used by the female as an energy source ( Voigt et al 2008) and the water content of the spermatophylax may provide benefits to the female at times of extreme water stress (Ivy et al 1999). Heller et al (1998) proposed that the high level of glycine present in the spermatophylax could indicate the presence of elastin-like structural proteins that increase the gummy consistency of the spermatophylax.…”

Polyandry Promotes Enhanced Offspring Survival in Decorated Crickets

“…Females can greatly influence the paternity of offspring through their ampulla-removal behavior, affording them an obvious mechanism by which they can selectively fertilize their eggs with the sperm of specific males (Sakaluk 1986;Sakaluk and Eggert 1996). Although the spermatophylax does not appear to provide G. sigillatus females with any detectable nutritional benefits (Will and Sakaluk 1994), previous work suggests that females benefit from ingesting the water contained in spermatophylaxes when they are water stressed (Ivy et al 1999). Thus, multiple mating in G. sigillatus may enable females to secure both material and genetic benefits, making it an ideal study system with which to study the effects of polyandry on female fitness.…”

“…When females discarded spermatophylaxes before they had been fully consumed, the partially eaten spermatophylax was recovered from the mating chamber with forceps and placed in the container housing the female. Females readily find and consume spermatophylaxes in this manner (Will and Sakaluk 1994;Ivy et al 1999). We ensured that females of different treatments were fully and equally inseminated by allowing males to guard females for a period of 50 min, approximately the time taken for the transfer of a complete ejaculate (Sakaluk 1984).…”