Looking for sexual selection in the female brain

Abstract

Female mate choice behaviour has significant evolutionary consequences, yet its mechanistic origins are not fully understood. Recent studies of female sensory systems have made great strides in identifying internal mechanisms governing female preferences. Only recently, however, have we begun to identify the dynamic genomic response associated with mate choice behaviour. Poeciliids provide a powerful comparative system to examine genomic responses governing mate choice and female preference behaviour, given the great range of mating systems: from female mate choice taxa with ornamental courting males to species lacking male ornamentation and exhibiting only male coercion. Furthermore, they exhibit laboratory-tractable preference responses without sexual contact that are decoupled from reproductive state, allowing investigators to isolate mechanisms in the brain without physiological confounds. Early investigations with poeciliid species ( Xiphophorus nigrensis and Gambusia affinis ) have identified putative candidate genes associated with female preference response and highlight a possible genomic pathway underlying female social interactions with males linked functionally with synaptic plasticity and learning processes. This network is positively correlated with female preference behaviour in the female mate choice species, but appears inhibited in the male coercive species. This behavioural genomics approach provides opportunity to elucidate the fundamental building blocks, and evolutionary dynamics, of sexual selection.

Perceptual Biases and Mate Choice

“…Females in many systems need to learn the difference between positive male phenotypes (courters who may provide direct or indirect benefits) relative to those who provide a negative interaction (coercive phenotypes such as sneakers or force copulators). Peak shift displacement could favor the elaboration of traits of the positive male phenotype in a direction that provides greater discrimination against coercive phenotypes (Cummings 2012). For instance, in many fishes, courting and coercive phenotypes differ in size, and females prefer the larger (noncoercive) phenotype.…”

Sexual selection and the evolution of behavior, morphology, neuroanatomy and genes in humans and other primates

“…These variables were tested in insects but are probably even more important in social mammals such as primates. Cummings (2012) recently reviewed these mechanisms in poeciliid fishes. Candidate genes were associated with female preferences and genomic pathways underlying female social interactions with males.…”

“…These genes are highly conserved across vertebrates. This mechanism probably functions in primates since there is behavioral evidence of experience-dependent mate choice across taxa from fish to birds and mammals (Cummings, 2012). So we have come full circle in a feedback system that links genes, gene expression, hormones, morphology, social structure and behavior.…”

Expression Patterns of Neuroligin-3 and Tyrosine Hydroxylase across the Brain in Mate Choice Contexts in Female Swordtails

“…Subsequent experiments localizing the expression of neuroserpin have identified possible brain regions involved in the processing of female mate choices . Given these characteristics, X. nigrensis represents a promising system to evaluate the neural and molecular mechanisms underlying female mate preference without the confounds of reproductive state and physical contact [Cummings, 2012].…”