title: Canalization of body size matters for lifetime reproductive success of male predatory mites (Acari: Phytoseiidae).
abstract: The adaptive canalization hypothesis predicts that highly fitness-relevant traits are canalized via past selection, resulting in low phenotypic plasticity and high robustness to environmental stress. Accordingly, we hypothesized that the level of phenotypic plasticity of male body size of the predatory mitesPhytoseiulus persimilis(low plasticity) andNeoseiulus californicus(high plasticity) reflects the effects of body size variation on fitness, especially male lifetime reproductive success (LRS). We first generated small and standard-sized males ofP. persimilisandN. californicusby rearing them to adulthood under limited and ample prey supply, respectively. Then, adult small and standard-sized males were provided with surplus virgin females throughout life to assess their mating and reproductive traits. Small male body size did not affect male longevity or the number of fertilized females but reduced male LRS ofP. persimilisbut notN. californicus. Proximately, the lower LRS of small than standard-sizedP. persimilismales correlated with shorter mating durations, probably decreasing the amount of transferred sperm. Ultimately, we suggest that male body size is more strongly canalized inP. persimilisthanN. californicusbecause deviation from standard body size has larger detrimental fitness effects inP. persimilisthanN. californicus.
authors.affiliation: Group of Arthropod Ecology and Behavior, Division of Plant Protection, Department of Crop Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82, 1190 Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Walzer
authors.affiliation: Group of Arthropod Ecology and Behavior, Division of Plant Protection, Department of Crop Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82, 1190 Vienna, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Schausberger
keywords: Neoseiulus californicus; Phytoseiulus persimilis; adaptive plasticity; environmental stress; mating behaviour; offspring sex-ratio; sexual selection