uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
The effects of male phenotypic condition on reproductive output in a sex role-reversed beetle
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. (Animal Ecology)
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
2015 (English)In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 102, 209-215 p.Article in journal (Refereed) Published
Abstract [en]

In insects with sex role reversal in mating, in which females actively court males, large and nutritious ejaculates are a common direct benefit to females. Such ejaculates are costly for males to produce and their size and composition can depend on male condition. However, the fitness effects to males and females of such condition-dependent provisioning are less clear. Here, we studied the effects of phenotypic condition on mating behaviour, ejaculate size and reproductive output in honeylocust beetles, Megabruchidius dorsalis. Our experimental design allowed us to disentangle the independent effects of juvenile resource acquisition in both sexes (as reflected by body size) and resource acquisition by adult males (feeding). We show that phenotypic condition of both sexes had sizeable independent and interactive effects on mating and reproductive output. In males, resources accrued during the juvenile phase had significant but relatively marginal effects on male mating and reproduction. Male adult feeding, in contrast, had sizeable effects on almost all aspects of male and female reproduction, through the nutritional effects of ejaculates in females. We discuss our findings in light of the reversal of both sex roles and sexual size dimorphism exhibited by this species, relative to related species. Our results highlight the importance of testing the interaction of male and female condition on components of fitness to understand the evolution and maintenance of mating systems.

Place, publisher, year, edition, pages
2015. Vol. 102, 209-215 p.
Keyword [en]
condition dependence, fecundity selection, nuptial gift, nutritious ejaculates, sex role reversal, sexual selection
National Category
Evolutionary Biology
URN: urn:nbn:se:uu:diva-246714DOI: 10.1016/j.anbehav.2015.01.025ISI: 000351058700021OAI: oai:DiVA.org:uu-246714DiVA: diva2:793938
Available from: 2015-03-09 Created: 2015-03-09 Last updated: 2015-07-07Bibliographically approved
In thesis
1. Sexual selection and the evolution of sex-role reversal in honeylocust beetles
Open this publication in new window or tab >>Sexual selection and the evolution of sex-role reversal in honeylocust beetles
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sexual selection is the prime evolutionary force that makes males and females different. This process has long been viewed as one where male compete with one another and where females choose. However, since the discovery that multiple mating by females is common in animals, sexual selection theory has been expanded to include mate competition between females and mate choice by males. However, empirical studies addressing these themes are scarce. In my thesis, I explore the evolution of sex role reversed mating systems using the honey locust beetles (Megabruchidius dorsalis and M. tonkineus). I used these species to shed light on (1) how closely sexual selection in females resembles its better‑studied male counterpart, (2) the implications of male mating costs for mating system evolution and (3) the effects of reproductive competition between females on the evolution of female courtship behaviour. By manipulating male mating rate, I found that males that mated more lived shorter lives, showing that mating is costly for males. I also demonstrated that males are choosy about whom they mate with and prefer vigorously courting females (Paper II). In contrast to males, previous studies suggested that female honey locust beetles benefit nutritionally from mating due to the large ejaculates provided by males. I manipulated male condition to show that male adult feeding had significant effects on female reproduction. Females that mated with males of good condition lived longer and produced more offspring than females whose mates were in poor condition (Paper III). When mating is costly for males, theory predicts that sexual selection in females can be strong. I compared sexual selection in honey locust beetles to that in two other species of seed beetles with conventional sex roles. I found substantial sexual selection in honey locust beetle females, which was comparable in strength to that in males (Paper I). I also measured the evolutionary effects of altered sex ratios on mating system parameters in both honey locust beetle species, using an experimental evolution design. Under female-biased sex ratios, representing strong sexual selection in females, females of M. dorsalis rapidly evolved elevated courtship intensity, thereby intensifying the reversal of sex roles (Paper V). In M. tonkineus, males evolved under male-biased sex ratios to transfer larger ejaculates, demonstrating the role of male-male reproductive competition for the evolution of male provisioning (Paper IV). My thesis highlights the essential, and often overlooked, role that females play in mating system evolution and that their contribution cannot simply be reduced to mate choice.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. 46 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1240
National Category
Evolutionary Biology
Research subject
Animal Ecology
urn:nbn:se:uu:diva-246715 (URN)978-91-554-9209-0 (ISBN)
Public defence
2015-05-13, Zootissalen, Evolutionary Biology Centre, Norbyvägen, Gamla Zoologen (Hus 1), Uppsala, 10:00 (English)
Available from: 2015-04-22 Created: 2015-03-09 Last updated: 2015-07-07

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Fritzsche, KarolineArnqvist, Göran
By organisation
Animal ecology
In the same journal
Animal Behaviour
Evolutionary Biology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 169 hits
ReferencesLink to record
Permanent link

Direct link