Understanding and challenging stereotypical sex differences in reproductive behaviours

Abstract

Evolutionary biology literature often suggests that the sexes express reproductive behaviours completely differently from one another, with stereotypical representations such as choosy females and competitive males. This thesis explores this concept at multiple levels from examining whether this is the actual perception of the research community to investigating overlooked behaviours like male mate choice and female-female competition. In chapter 2, I conducted a survey in which I asked participants about their perceptions on sex differences in reproductive behaviours in non-human animals. I found that although people agree with the stereotypical roles proposed in the literature, they understand variation exists around these stereotypes. More importantly, I found that personal and research experiences from participants were associated with their perception about sex differences, revealing potential sources of biases about this topic. In chapter 3, I assessed whether male mate choice occurs in the praying mantis Miomantis caffra, in which females often cannibalize males before copula. I found evidence that males express mate preferences in that species and that males’ personality (activity) was associated with differences in approaching behaviour to females, showing that the common stereotype of males always being eager to mate is not true. In chapter 4, I conducted a meta-analysis across all animals to evaluate whether male mate choice varies among individuals. I found that, on average, higher quality males (e.g. larger and in better body condition) are choosier than their counterparts. Finally, in chapter 5, I explored whether mate competition in humans impacts their same-gender friendships. More specifically, I hypothesized that physical similarity in same-gender friendships would be more prominent for women than for men. This is because physical traits are often mentioned by men to determine mates’ attractiveness and thus could be a potential source of rivalry in friendships between women. I found no support that men and women choose friends differently. Altogether, I show that the simplifications of sex differences that stereotypes convey can conceal complexities found in nature.