Extreme Costs of Mating for Male Two-Spot Ladybird Beetles

Male costs of mating are now thought to be widespread. The two-spot ladybird beetle (Adalia bipunctata) has been the focus of many studies of mating and sexual selection, yet the costs of mating for males are unknown. The mating system of A. bipunctata involves a spermatophore nuptial gift ingested by females after copulation. In this study, we investigate the cost to males of mating and of transferring spermatophores in terms of lifespan, ejaculate production and depletion of nutritional reserves. We found that males faced a strong trade-off between mating and survival, with males that were randomly assigned to mate a single time experiencing a 53% reduction in post-mating lifespan compared to non-mating males. This is among the most severe survival costs of a single mating yet reported. However, spermatophore transfer did not impact male survival. Instead, the costs associated with spermatophores appeared as a reduced ability to transfer spermatophores in successive matings. Furthermore, males ingested more food following spermatophore transfer than after matings without spermatophores, suggesting that spermatophore transfer depletes male nutritional reserves. This is to our knowledge the first report of an effect of variation in copulatory behaviour on male foraging behaviour. Overall, our study highlights the advantages of assessing mating costs using multiple currencies, and suggests that male A. bipunctata should exhibit mate choice

New information on the evolution of mating behaviour in Sepsidae (Diptera) and the cost of male copulations in Saltella sphondylii

10.1007/s13127-011-0054-2Organisms Diversity and Evolution114253-261ODER

Polygyny in the olive fly-effects on male and female fitness

Polygynous males must balance their limited ejaculate resources between current copulations, with putative future ones. Working on olive flies (Bactrocera oleae), our objectives were to determine (a) how males budget sperm to consecutive copulations, (b) what costs consecutive copulations incur, and (c) how male mating history affects female fecundity, fertility, and longevity. We allowed males to copulate with virgin females on successive days and monitored the fertility and fecundity of these females, and the longevity of both sexes. We found that as males gained sexual experience, latency to mate declined significantly, while copula duration increased. The number of sperm stored by females declined according to the sexual history of her mate-as males gained experience, significantly fewer sperm cells were transferred. Mated males suffered a significant longevity cost compared to virgin ones, but this cost was not compounded by additional matings. Male sexual experience affected both female fecundity and fertility. Furthermore, mating with an experienced male incurred a longevity cost to females. We conclude that non-sperm components of the male ejaculate are responsible for reducing female fecundity, fertility, and longevity, and predict that females should prefer to mate with virgin males

Dissecting the mechanisms underlying old male mating advantage in a butterfly

Selection is expected to maximize an individual’s own genetic reward regardless of the potential fitness consequences for its sexual partners, which may cause sexual conflict. Although performance in holometabolous insects typically diminishes with age, old male mating advantage has been documented in a few species. Whether this pattern arises from female preference for older males based on, e.g., pheromone blends (intersexual selection), or from increased eagerness to mate in older compared to younger males is currently debated. We explore the mechanistic basis of old male mating advantage, using a series of experiments including behavioral as well as manipulative approaches, in the tropical butterfly Bicyclus anynana. Consistent with the residual reproductive value hypothesis, old male mating advantage was associated with a greater eagerness to mate, evidenced by a two times higher flying and courting activity in older than in younger males. In contrast, we found only limited support for a contribution of female preference for older males based on pheromone composition, although male sex pheromones clearly do play a role in mating success. Our results suggest that male behavior may play a primary role in old male mating advantage, and that pheromones are likely of secondary importance only. Male mating success was related to higher overall pheromone titers rather than variation in a single component. A dominant importance of male behavior in determining mating success may result in sexual conflict