The significant role of post-pairing male behavior on the evolution of male preferences and female traits

Nan Lyu,Huw Lloyd,D Justin Yeh,Yue-Hua Sun

doi:10.1038/s42003-021-02961-x

Abstract

Existing sexual selection theory postulates that a sufficiently large variation in female fecundity or other direct benefits are fundamental for generating male mate choice. In this study, we suggest that, in addition to pre-pairing preferences, choosy males can also have different post-pairing behaviors, a factor which has been comparatively overlooked by previous studies. We found that both male preferences and female traits could evolve much more easily than previously expected when the choosy males that paired with unpreferred females would allocate more efforts to seeking additional post-pairing mating opportunities. Furthermore, a costly female trait could evolve when there was a trade-off between seeking additional mating and paternal care investment within social pair for choosy males. Finally, a costly male preference and a costly female trait might still evolve and reach a stable polymorphic state in the population, which might give rise to a high variability in male choice and female traits in nature. We suggest that male mate choice may be even more common than expected, which needs to be verified empirically.

Highlights

Existing sexual selection theory postulates that a sufficiently large variation in female fecundity or other direct benefits are fundamental for generating male mate choice
If T1 females choose to mate with P2 males, the preference for T2 females might drive those P2 males to reduce their investment in breeding within social pair, which in turn enables them to have more effort to seeking additional matings
Following the inclusion of male post-pairing behavior into our sexual selection model, we show that male preferences and female traits can evolve even without direct benefits for female traits, such as the higher female fecundity and/or quality[11]

Summary

Introduction

Existing sexual selection theory postulates that a sufficiently large variation in female fecundity or other direct benefits are fundamental for generating male mate choice. In previous sexual selection models, male mate choice has been widely assumed to take effect during the pre-pairing period, i.e., choosy males exhibit divergent mating tendencies for females with or without the preferred signaling traits[9]. Some empirical studies have indicated that males within a population may vary extensively in additional mating efforts[29], or even have the flexibility to take the initiative to vary their effort allocation between additional mating and reproduction within social pair[30] This mechanism of post-pairing male choicegenerating sexual selection for female traits has comparatively seldom been studied[31] or considered by theoretical models that explore the evolution of male mate choice This mechanism of post-pairing male choicegenerating sexual selection for female traits has comparatively seldom been studied[31] or considered by theoretical models that explore the evolution of male mate choice (but see refs. 15,32)

Methods

Results

Conclusion