Preprint: Please note that this article has not completed peer review.

A LIFE-HISTORY PERSPECTIVE ON SEXUAL SELECTION IN A POLYGAMOUS SPECIES

Gao Ke, Michiel van Wijk, Zoe Clement, Martijn Egas, Astrid Groot

Abstract

Background

Ever since Darwin, evolutionary biologists have studied sexual selection driving differences in appearance and behaviour between males and females. An unchallenged paradigm in such studies is that one sex (usually the male) signals its quality as a mate to the other sex (usually the female), who is choosy in accepting a partner. Here, we argue that in polygamous species these roles may change dynamically with the mating status of males and females, depending on direct reproductive costs and benefits of multiple matings, and on sperm competition. We test this hypothesis using a polygamous moth species, as in moths not males but females are the signalers and males are the responders.

Results

We found that multiple matings are beneficial as well as costly for both sexes. Specifically, the number of matings did not affect the longevity of males or females, but when paired with a new virgin mate every night for five nights, only 67% of the males and 14% of the females mated successfully in all five nights. The female’s reproductive output increased with multiple matings, although when paired with a new virgin male every night, additional matings beyond 3 decreased her reproductive output, so that the Bateman gradient for females fit a quadratic model better than a linear model. The male’s reproductive success was positively affected by the number of matings and a linear regression line best fit the data. Simulations of the effect of sperm competition showed that increasing last-male paternity increases the steepness of the male Bateman gradient and thus the male’s relative fitness gain from additional mating. Irrespective of last-male paternity value, the female Bateman gradient is steeper than the male one for up to three matings.

Conclusion

Our results suggest that choosiness in moths may well change throughout the mating season, with males being more choosy early in the season and females being more choosy after having mated at least three times. This life-history perspective on the costs and benefits of multiple matings for both sexes sheds new light on sexual selection forces acting on sexual signals and responses.

Keywords
sexual selection, polygamous species

Figures

Background

Results

Discussion

Conclusions

Methods

Declarations

References

Table

Additional File

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Preprint: Please note that this article has not completed peer review.

A LIFE-HISTORY PERSPECTIVE ON SEXUAL SELECTION IN A POLYGAMOUS SPECIES

Gao Ke, Michiel van Wijk, Zoe Clement, Martijn Egas, Astrid Groot

STATUS: In Review

Comments: 0
PDF Downloads: 0
HTML Views: 1

Integrity Check:

  • Article

  • Peer Review Timeline

  • Related Articles

  • Comments

Abstract

Background

Ever since Darwin, evolutionary biologists have studied sexual selection driving differences in appearance and behaviour between males and females. An unchallenged paradigm in such studies is that one sex (usually the male) signals its quality as a mate to the other sex (usually the female), who is choosy in accepting a partner. Here, we argue that in polygamous species these roles may change dynamically with the mating status of males and females, depending on direct reproductive costs and benefits of multiple matings, and on sperm competition. We test this hypothesis using a polygamous moth species, as in moths not males but females are the signalers and males are the responders.

Results

We found that multiple matings are beneficial as well as costly for both sexes. Specifically, the number of matings did not affect the longevity of males or females, but when paired with a new virgin mate every night for five nights, only 67% of the males and 14% of the females mated successfully in all five nights. The female’s reproductive output increased with multiple matings, although when paired with a new virgin male every night, additional matings beyond 3 decreased her reproductive output, so that the Bateman gradient for females fit a quadratic model better than a linear model. The male’s reproductive success was positively affected by the number of matings and a linear regression line best fit the data. Simulations of the effect of sperm competition showed that increasing last-male paternity increases the steepness of the male Bateman gradient and thus the male’s relative fitness gain from additional mating. Irrespective of last-male paternity value, the female Bateman gradient is steeper than the male one for up to three matings.

Conclusion

Our results suggest that choosiness in moths may well change throughout the mating season, with males being more choosy early in the season and females being more choosy after having mated at least three times. This life-history perspective on the costs and benefits of multiple matings for both sexes sheds new light on sexual selection forces acting on sexual signals and responses.

Figures

Background

Results

Discussion

Conclusions

Methods

Declarations

References

Table

Additional File

Learn more about our company.