Clarissa M. House

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In animals with internal fertilization and promiscuous mating, male genitalia show rapid and divergent evolution. Three hypotheses have been suggested to explain the evolutionary processes responsible for genital evolution: the lock-and-key hypothesis, the pleiotropy hypothesis and the sexual-selection hypothesis. Here, we determine whether variation in(More)
Animals of many species accept or solicit recurring copulations with the same partner; i.e., show repeated mating. An evolutionary explanation for this excess requires that the advantages of repeated mating outweigh the costs, and that behavioral components of repeated mating are genetically influenced. There can be benefits of repeated mating for males(More)
Three main hypotheses, have been invoked to explain divergent genital evolution, the lock and key, pleiotropy, and sexual selection hypotheses, each of which make different predictions about how genital traits are inherited. Here we used a half-sib breeding design to examine the patterns of genetic variation and covariation between male genital sclerites,(More)
Sexual selection is a major force driving the evolution of elaborate male sexual traits. Handicap models of sexual selection predict that male sexual traits should covary positively with condition, making them reliable indicators of male quality. However, most studies have either manipulated condition through varying diet quantity and/or caloric content(More)
Fertilization success in sperm competition is often determined by laboratory estimates of the proportion of offspring sired by the first (P1) or second (P2) male that mates. However, inferences from such data about how sexual selection acts on male traits in nature may be misleading if fertilization success depends on the biological context in which it is(More)
The existence of genetic variation in offspring size in plants and animals is puzzling because offspring size is often strongly associated with fitness and expected to be under stabilizing selection. An explanation for variation in seed size is conflict between parents and between parents and offspring. However, for this hypothesis to be true, it must be(More)
Male genital morphology is characterized by two striking and general patterns of morphological variation: rapid evolutionary divergence in shape and complexity, and relatively low scaling relationships with body size. These patterns of variation have been ascribed to the action of sexual selection. Among species, monogamous taxa tend to have relatively less(More)
Sexual selection is responsible for the evolution of many elaborate traits, but sexual trait evolution could be influenced by opposing natural selection as well as genetic constraints. As such, the evolution of sexual traits could depend heavily on the environment if trait expression and attractiveness vary between environments. Here, male Drosophila(More)
We examine the condition-dependence of male genitalia in the dung beetle Onthophagus taurus by manipulating the quality of dung provided for larval growth and development. We show that the influence of larval nutrition differed considerably across three different trait classes (sexual, nonsexual and genital). The size of all nonsexual traits varied with(More)