title: Selection for predation, not female fecundity, explains sexual size dimorphism in the orchid mantises.
abstract: Here we reconstruct the evolutionary shift towards floral simulation in orchid mantises and suggest female predatory selection as the likely driving force behind the development of extreme sexual size dimorphism. Through analysis of body size data and phylogenetic modelling of trait evolution, we recovered an ancestral shift towards sexual dimorphisms in both size and appearance in a lineage of flower-associated praying mantises. Sedentary female flower mantises dramatically increased in size prior to a transition from camouflaged, ambush predation to a floral simulation strategy, gaining access to, and visually attracting, a novel resource: large pollinating insects. Male flower mantises, however, remained small and mobile to facilitate mate-finding and reproductive success, consistent with ancestral male life strategy. Although moderate sexual size dimorphisms are common in many arthropod lineages, the predominant explanation is female size increase for increased fecundity. However, sex-dependent selective pressures acting outside of female fecundity have been suggested as mechanisms behind niche dimorphisms. Our hypothesised role of predatory selection acting on females to generate both extreme sexual size dimorphism coupled with niche dimorphism is novel among arthropods.
authors.affiliation: Department of Invertebrate Zoology, Cleveland Museum of Natural History, Cleveland, Ohio, United States of America.|Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Svenson
authors.affiliation: Department of Invertebrate Zoology, Cleveland Museum of Natural History, Cleveland, Ohio, United States of America.|Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Sydney K
authors.initials: SK
authors.lastname: Brannoch
authors.affiliation: Department of Invertebrate Zoology, Cleveland Museum of Natural History, Cleveland, Ohio, United States of America.|Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Henrique M
authors.initials: HM
authors.lastname: Rodrigues
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, Australia.
authors.forename: James C
authors.initials: JC
authors.lastname: O'Hanlon
authors.affiliation: Pfalzmuseum für Naturkunde - POLLICHIA-Museum, Bad Dürkheim, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Wieland
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D049628:Body Size; D005260:Female; D008297:Male; D020050:Mantodea / Q000502:physiology*; D010802:Phylogeny; D054817:Pollination; D011235:Predatory Behavior; D012044:Regression Analysis; D012098:Reproduction; D012641:Selection, Genetic; D012727:Sex Characteristics