Behavioral Ecology Advance Access published online on June 8, 2009
Behavioral Ecology, doi:10.1093/beheco/arp072
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Condition-dependent mate choice and its implications for population differentiation in the wolf spider Pirata piraticus
a Terrestrial Ecology Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium b Department of Entomology, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
Address correspondence to D. Eraly. E-mail: debbie.eraly{at}ugent.be.
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Abstract |
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When populations face different environmental conditions, both local adaptation and phenotypic plasticity may cause interpopulation divergence of behavioral or phenotypic properties on which mate choice is based. If sustained, this may result in genetic differentiation even in the presence of extant gene flow. Condition dependence of mate choice is one of the main mechanisms explaining these environmental effects. We tested whether experimental food stress affects mate choice in male and female Pirata piraticus spiders from one heavily polluted and one unpolluted reference population. Compared with control females, food-stressed females from the reference population showed a decreased probability of copulation and preferred smaller mates. Females from the polluted population, in contrast, did not show a significant response to food stress and showed size-assortative mating, most strongly under food stress. We explain these results in 2 complementary ways. First, spiders from populations that are not adapted to cope with stress may be less willing to mate when eggs are not fully matured. Second, food-deprived females may show a larger responsiveness toward smaller males because the latter resemble prey more and hungry females tend to attack moving objects more often. Results from this study support the prediction that variation in body condition, driven by local ecological factors, may affect mating behavior and may ultimately lead to population divergence in important life-history traits such as body size.
Key words: heavy metals, phenotypic plasticity, population divergence, reproductive isolation, resource availability, sexual selection, size-assortative mating.
Received 29 October 2008; revised 28 April 2009; accepted 5 May 2009.