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Intersexual Resource Competition and the Evolution of Sex-Biased Dispersal


Li, Xiang-Yi; Kokko, Hanna (2019). Intersexual Resource Competition and the Evolution of Sex-Biased Dispersal. Frontiers in Ecology and Evolution:7:111.

Abstract

Resource competition is a major driver of dispersal: an emigrating individual leaves more resources to its kin. Existing models of sex-biased dispersal rarely consider intersexual competition for resources. Instead, male reproductive success is often solely assumed to depend on female availability, implying a tacit assumption that male presence never depletes resources, such as food, that are of interest to female kin. In reality, both male and female offspring typically consume resources on their natal site before departing to consume resources elsewhere, and sexually dimorphic body sizes imply that the resource needs can differ. The goal of our study is to investigate how intersexual competition for resources can affect the evolution of sex-specific dispersal, via competition between kin of the same sex or different sexes and the subsequent success elsewhere. Our individual-based simulation model allows not only the dispersal probability but also its timing to evolve. We consider dispersal timing because later dispersal yields a longer period of kin competition than dispersal that occurs soon after independence. We also highlight the role of sex-specific income/capital breeding strategies, which is understudied in both empirical and theoretical literature of sex-specific dispersal. We show that sex biases in dispersal probability and timing are sensitive to the presence of intersexual competition, sexual differences in capital vs. income breeding strategies, and sexual dimorphism in the quantity of resources consumed. Males may evolve to disperse earlier if they also consume more food, as a result of selection to reduce intersexual kin competition. Alternatively, males may evolve to disperse less as well as later than females, if male fitness depends more on resource accumulation (e.g., building a large body to succeed in mating competition under polygyny) whereas female fitness depends more on reliable income (e.g., in species that require extended periods of maternal foraging), even if both sexes are equally competitive in consuming resources. Although the more dispersive sex is often the earlier departing sex, we also find cases where the only clear dimorphism is found in dispersal timing. We thus encourage more studies on the timing aspect of sex-biased dispersal.

Abstract

Resource competition is a major driver of dispersal: an emigrating individual leaves more resources to its kin. Existing models of sex-biased dispersal rarely consider intersexual competition for resources. Instead, male reproductive success is often solely assumed to depend on female availability, implying a tacit assumption that male presence never depletes resources, such as food, that are of interest to female kin. In reality, both male and female offspring typically consume resources on their natal site before departing to consume resources elsewhere, and sexually dimorphic body sizes imply that the resource needs can differ. The goal of our study is to investigate how intersexual competition for resources can affect the evolution of sex-specific dispersal, via competition between kin of the same sex or different sexes and the subsequent success elsewhere. Our individual-based simulation model allows not only the dispersal probability but also its timing to evolve. We consider dispersal timing because later dispersal yields a longer period of kin competition than dispersal that occurs soon after independence. We also highlight the role of sex-specific income/capital breeding strategies, which is understudied in both empirical and theoretical literature of sex-specific dispersal. We show that sex biases in dispersal probability and timing are sensitive to the presence of intersexual competition, sexual differences in capital vs. income breeding strategies, and sexual dimorphism in the quantity of resources consumed. Males may evolve to disperse earlier if they also consume more food, as a result of selection to reduce intersexual kin competition. Alternatively, males may evolve to disperse less as well as later than females, if male fitness depends more on resource accumulation (e.g., building a large body to succeed in mating competition under polygyny) whereas female fitness depends more on reliable income (e.g., in species that require extended periods of maternal foraging), even if both sexes are equally competitive in consuming resources. Although the more dispersive sex is often the earlier departing sex, we also find cases where the only clear dimorphism is found in dispersal timing. We thus encourage more studies on the timing aspect of sex-biased dispersal.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Evolutionary Biology and Environmental Studies
Dewey Decimal Classification:570 Life sciences; biology
590 Animals (Zoology)
Language:German
Date:9 April 2019
Deposited On:04 Dec 2019 15:45
Last Modified:04 Dec 2019 15:48
Publisher:Frontiers Research Foundation
ISSN:2296-701X
OA Status:Gold
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.3389/fevo.2019.00111
Project Information:
  • : FunderSNSF
  • : Grant IDPZ00P3_180145
  • : Project TitleTowards a more biologically informed evolutionary game theory
  • : FunderSNSF
  • : Grant ID31003A_163374
  • : Project TitleSex, sexual selection and local adaptation

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