title: Behavioral adaptations imply a direct link between ecological specialization and reproductive isolation in a sympatrically diverging ground beetle.
abstract: Adaptation to a previously unoccupied niche within a single population is one of the most contentious topics in evolutionary biology as it assumes the simultaneous evolution of ecologically selected and preference traits. Here, we demonstrate behavioral adaptation to contrasting hydrological regimes in a sympatric mosaic of Pogonus chalceus beetle populations, and argue that this adaptation may result in nonrandom gene flow. When exposed to experimental inundations, individuals from tidal marshes, which are naturally subjected to frequent but short floods, showed a higher propensity to remain submerged compared to individuals from seasonal marshes that are inundated for several months. This adaptive behavior is expected to decrease the probability that individuals will settle in the alternative habitat, resulting in spatial sorting and reproductive isolation of both ecotypes. Additionally, we show that this difference in behavior is induced by the environmental conditions experienced by the beetles during their nondispersive larval stages. Hence, accidental or forced ovipositioning in the alternative habitat may induce both an increased performance and preference to the natal habitat type. Such plastic traits could play an important role in the most incipient stages of divergence with gene flow.
authors.affiliation: Terrestrial Ecology Unit, Biology Department, Ghent University, B-9000 Gent, Belgium. VanBelleghemSteven@hotmail.com.|Royal Belgian Institute of Natural Sciences, Entomology Department, 1000 Brussels, Belgium. VanBelleghemSteven@hotmail.com.|Department of Biology, Center for Applied Tropical Ecology and Conservation, University of Puerto Rico, Rio Piedras, Puerto Rico. VanBelleghemSteven@hotmail.com.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Van Belleghem
authors.affiliation: Terrestrial Ecology Unit, Biology Department, Ghent University, B-9000 Gent, Belgium.|Royal Belgian Institute of Natural Sciences, Entomology Department, 1000 Brussels, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: De Wolf
authors.affiliation: Terrestrial Ecology Unit, Biology Department, Ghent University, B-9000 Gent, Belgium.|Royal Belgian Institute of Natural Sciences, Entomology Department, 1000 Brussels, Belgium.
authors.forename: Frederik
authors.initials: F
authors.lastname: Hendrickx
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D001530:Belgium; D001517:Coleoptera / Q000235:genetics / Q000502:physiology*; D055868:Floods; D005602:France; D051456:Gene Flow; D000071421:Life History Traits; D060047:Reproductive Isolation; D061350:Sympatry
keywords: Assortative mating; local adaptation; magic trait; matching habitat choice; natal habitat preference; phenotypic plasticity