Variation in male and female mating behaviour among different populations of the two-spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)

Penelope R. HADDRILL,Michael E.N. MAJERUS,David M. SHUKER

doi:10.14411/eje.2013.011

Penelope R. HADDRILL, Michael E.N. MAJERUS + Show 1 more

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https://doi.org/10.14411/eje.2013.011

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Abstract

Investigating the function of both male and female mating behaviours is essential in our attempts to understand the evolution of mating systems. Variation in mating behaviours among different populations within a species provides a useful opportunity to explore how behaviours may co-vary, although comparative studies are still rather few in number. Population variation in mating behaviour may also have important implications in terms of the evolution of reproductive isolation, the distribution of genetic diversity within and between populations, and the associated ability of those populations to adapt. Here we consider male and female mating behaviour in two populations of the two-spot ladybird, Adalia bipunctata, from the UK and Russia. We find that male and female mating behaviours differ between the populations in terms of the length of female rejection behaviour and the duration of mating, and that this variation is independent of which population an individual's mating partner is from. Our data confirm that patterns of sexual selection and reproductive behaviour are likely to vary across populations in the two-spot ladybird. The extent to which this variation is due to current ecological factors or population history remains to be verified for this species, as for many others.

Highlights

Understanding both male and female mating behaviours, and the roles they play in determining mating outcomes, is essential if we are to determine the relative importance of the two sexes in the evolution of mating systems, and the extent to which these systems are dominated by sexual conflict and sexually antagonistic evolution (Arnqvist & Rowe, 2005)
We examined the rejection and mating behaviour of both male and female two-spot ladybirds originating from populations in the UK and Russia, in order to test first whether ladybird behaviour varies across populations, and second if such variation depended on whether individuals encounter mating partners from the same population of origin as their own, or from a different population
Components of both the male and female mating behaviour repertoire differed between the two populations, with the most notable being female rejection behaviour and male insemination behaviour

Summary

Introduction

Understanding both male and female mating behaviours, and the roles they play in determining mating outcomes, is essential if we are to determine the relative importance of the two sexes in the evolution of mating systems, and the extent to which these systems are dominated by sexual conflict and sexually antagonistic evolution (Arnqvist & Rowe, 2005). For example, sex ratio, density, resource availability, the presence of predators, or any number of other ecological variables, there may be substantial differences in the strength of sexual selection and in the optimal mating rate for either or both of the two sexes (e.g. Kokko & Rankin, 2006) Studies documenting such variation are less common than single-population studies, limiting our view of, for example, how mating behaviour varies across a species range. Whatever the forces determining their evolution, differences in mating behaviours between populations are likely to lead to differences in the variance in reproductive success between the sexes, and between populations This has important implications for both the strength and direction of sexual selection, and the relative effective population sizes of the sexes and the different populations. This will in turn influence the distribution of genetic diversity within and between populations and the associated ability of those populations to adapt (Nunney, 1993; Caballero, 1995; Charlesworth, 2001)

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