Why Males Compete Rather Than Care, with an Application to Supplying Collective Goods
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Why Males Compete Rather Than Care, with an Application to Supplying Collective Goods Sara L Loo1 · Danya Rose2 · Michael Weight3 · Kristen Hawkes3 · Peter S Kim2 Received: 31 October 2019 / Accepted: 31 August 2020 © Society for Mathematical Biology 2020
Abstract The question of why males invest more into competition than offspring care is an ageold problem in evolutionary biology. On the one hand, paternal care could increase the fraction of offspring surviving to maturity. On the other hand, competition could increase the likelihood of more paternities and thus the relative number of offspring produced. While drivers of these behaviours are often intertwined with a wide range of other constraints, here we present a simple dynamic model to investigate the benefits of these two alternative fitness-enhancing pathways. Using this framework, we evaluate the sensitivity of equilibrium dynamics to changes in payoffs for male allocation to mating versus parenting. Even with strong effects of care on offspring survivorship, small competitive benefits can outweigh benefits from care. We consider an application of the model that includes men’s competition for hunting reputations where big game supplies a benefit to all and find a frequency-dependent parameter region within which, depending on initial population proportions, either strategy may outperform the other. Results demonstrate that allocation to competition gives males greater fitness than offspring care for a range of circumstances that are dependent on life-history parameters and, for the large-game hunting application, frequency dependent. The greater the collective benefit, the more individuals can be selected to supply it. Keywords Male competition · Paternal care · Mating effort · Ordinary differential equations · Large-game hunting
S. Loo and D. Rose contributed comparably.
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Sara L Loo [email protected]
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School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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School of Mathematics and Statistics, University of Sydney, Sydney, NSW 2006, Australia
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Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA 0123456789().: V,-vol
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1 Introduction Parental care and mating competition are two components of reproductive effort that offer distinct fitness-related payoffs. The first of these reproductive strategies, parental care, contributes to the differential welfare or reproductive success of current offspring, here indexed by differential survivorship. A separate path, mating competition, contributes to the chance of additional conceptions. Both sexes are faced with an allocation problem—does one invest reproductive effort into parental care or into mating competition (Houston et al. 2005; Klug et al. 2012; McNamara et al. 2000; Parker et al. 2002; Trivers 1972)? Observations of this problem by many early commentators (Bateman 1948; Darwin 1859, 1874; Fisher 1930; Trivers 1972) found that in a wide range of taxa, including many mam
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