Experimental coevolution of male and female genital morphology

Abstract

male genitalia typically exhibit patterns of rapid and divergent evolution, and there is now considerable evidence that sexual selection is an important driver of these patterns of phenotypic variation. Female genitalia have been less well studied, and are generally thought to be relatively invariant. Here we use experimental evolution to show that sexual selection drives the correlated evolution of female and male genital morphology in the scarabaeine dung beetle Onthophagus taurus. moreover, we use quantitative genetic analyses to provide a rare insight into the genetic architecture underlying morphological variation in female genital morphology, and uncover evidence of the genetic covariation with male genital morphology that is expected to arise under persistent sexual selection.

Mechanisms and Evidence of Genital Coevolution: The Roles of Natural Selection, Mate Choice, and Sexual Conflict

“…via sexual conflict (Cayetano et al 2011). After 19 generations of sexual selection compared to enforced monogamy, the genital pits of female dung beetles (in which the parameres at the tip of the aedagus will anchor) become smaller and get closer and thus harder to reach, while the shape of their aedagus (external genitalia) changes in males (Simmons and García-González 2011). An interspecific phylogenetic study in dung beetles detected coevolution between the shape of the parameres and the female pygidial flap morphology in which the parameres fit into before intromission (Macagno et al 2011).…”

“…via female choice (Simmons and García-González 2011) and seed beetles (Callosobruchus sp.) via sexual conflict (Cayetano et al 2011).…”

“…For this reason alone, coevolution between genital morphologies of males and females is expected. Morphological and genetic components of male and female genitalia have been shown to covary in many taxa (Sota and Kubota 1998;Ilango and Lane 2000;Arnqvist and Rowe 2002;Brennan et al 2007;Rönn et al 2007;Kuntner et al 2009;Tatarnic and Cassis 2010;Cayetano et al 2011;Evans et al 2011Evans et al , 2013Simmons and García-González 2011;Yassin and Orgogozo 2013; and see examples in Table 1). The likely mechanism is that suggested by the authors, and it includes sexually antagonistic coevolution (SAC), natural selection, sexual selection, female choice, or none specified.…”

Sexual conflict and the function of genitalic claws in guppies (Poecilia reticulata)

“…Although most of the evidence we have for the role of sexual selection in genital evolution tends to be correlative [3], a few recent studies provide more direct evidence from the experimental evolution of genitalia [8][9][10] or phenotypic manipulations of genital features [6,7,[10][11][12][13][14][15]. These latter 'phenotypic engineering' studies are particularly informative, because they focus directly on function and offer the promise of finely distinguishing among alternative mechanisms of selection, unimpeded by unmeasured correlated traits.…”

Digest: Ontogenesis and evolutionary allometry shape divergent evolution of genitalia in female cetaceans*

“…In contrast, female genitalia are not as well studied, as they are generally thought to be relatively invariant (Ah-King et al 2014). However, it has been shown that the coevolution between male and female genitalia is expected to result from close mechanical interactions during the copulating process (Simmons and Garcia-Gonzalez 2011 adaptations, it is still very important to identify this pattern and confirm the potential evolutionary drivers of genital variation (Brennan and Prum 2015).…”