Male mate choice and selectivity in relation to female body size, in the seed beetle Callosobruchus maculatus
Master thesis
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Date
2019-06-21Metadata
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- Master theses [289]
Abstract
Selectivity in mate choice and mating behaviour is a central element of sexual selection, and an important component of evolution in a number of species across the animal kingdom. Mate choice relates to how individuals respond to the phenotypic traits of potential mates in order to maximize their own fitness. As most studies on sexual selection concentrate on female mate choice, it is interesting to investigate to what extent male choice may play a role in evolution. In the seed beetle Callosobruchus maculatus males are paying a significant cost when mating, by inseminating the female with a large spermatophore. There is also differences in fitness consequences when choosing mates, as larger females generally show higher fecundity. These factors may select for male mate choice, but whether male C. maculatus are able to discriminate between females of different size and be selective in their mating behaviour, is currently unknown. This study takes an experimental approach to investigate whether males discriminate between females of different weight, both when choosing mates and in their energy investment during copulation. Results indicate that males do not show any mating preference in their first mating, and do not transfer bigger spermatophores when copulating with larger females. However, as this study only focuses on the male’s first mating after isolation, it is still possible that male choice becomes more important later when they are exposed to more mates.