Interspecific variation in ejaculate allocation and associated effects on female fitness in seed beetles
2008 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 21, no 2, 461-470 p.Article in journal (Refereed) Published
When ejaculates are costly to produce, males are expected to allocate their ejaculate resources over successive matings in a manner that optimises their reproductive success. Theory predicts that two factors should affect optimal ejaculate allocation: the sperm competition regime and variation in female fecundity. In seed beetles (Bruchidae), ejaculates vary in size across species from weighing a few, up to as much as twelve percent, of male body weight. Ejaculates in this group contain not only sperm but also a range of additional substances and it has been proposed that females gain benefits from receiving large ejaculates. Male ejaculate allocation may thus affect female fitness and, indirectly, his own reproductive output. Here, we first measured how males allocate ejaculates over successive matings in seven seed beetle species. We then assessed how this allocation affected female fitness. We found that ejaculate weight drops dramatically over successive matings in some species but not in others. This interspecific variation in ejaculate allocation pattern was matched with extensive variation in the effects of ejaculate allocation on female fitness. Species varied both in terms of the size of the effect of male mating history on female fitness and in terms of which female fitness components were affected. In summary, despite the fact that the species included in this study are closely related, interspecific variation in ejaculate allocation patterns and their effects on female fitness was remarkably large. We discuss the possible causes of this variation and its implications for male-female coevolution.
Place, publisher, year, edition, pages
2008. Vol. 21, no 2, 461-470 p.
acessory gland products, Callosobruchus, nuptial gifts, sperm allocation
IdentifiersURN: urn:nbn:se:su:diva-61563DOI: 10.1111/j.1420-9101.2007.01493.xOAI: oai:DiVA.org:su-61563DiVA: diva2:436327