Nuptial feeding by male bushcrickets: an indicator of male quality?

Male bushcrickets transfer a spermatophore at mating that consists of a spe rm-containing ampulla and a product of the accessory glands, the spermatoph ylax, that is consumed by the female during insemination. Male Requena vati calis produce functionally different spermatophores depending on the availa bility of sexually receptive females. They will maintain high mating freque ncy by providing a gift sufficient to ensure sperm transfer, or will invest parentally in females when their mating frequency is low. We examined the relationship between male quality and nuptial feeding under conditions wher e males invest in ejaculate protection or in parental investment. When inve sting in ejaculate protection, males reduced the quality of the spermatophy lax meal by I educing both the concentration of protein and the absolute am ount of protein it contained. There was no relationship between male phenot ype and gift size or quality. Moreover, we could find no evidence for the r ecently advanced hypothesis that females can exercise mate choice by interf ering with insemination. However, when males were investing parentally, we found a positive association between spermatophylax size and male size, but no relationship between protein content and male size. Males with high lev els of fluctuating asymmetry invested more heavily in the nutritional conte nt of their spermatophylaxes than did symmetrical males. Thus, male quality does influence nuptial feeding, but in a manner predicted by a model of in direct fitness benefits from mate choice.