title: Changes in composition of cuticular biochemicals of the facultatively polygynous ant Petalomyrmex phylax during range expansion in Cameroon with respect to social, spatial and genetic variation.
abstract: In social insects, biochemicals found at the surface of the cuticle are involved in the recognition process and in protection against desiccation and pathogens. However, the relative contribution of evolutionary forces in shaping diversity of these biochemicals remains largely unresolved in ants. We determined the composition of epicuticular biochemicals for workers sampled in 12 populations of the ant Petalomyrmex phylax from Cameroon. Genetic variation at 12 microsatellite markers was used to infer population history and to provide null expectations under the neutrality hypothesis. Genetic data suggest a recent southward range expansion of this ant species. Furthermore, there is a decline southward in the numbers of queens present in mature colonies. Here, we contrast the pattern of biochemical variation against genetic, social and spatial parameters. We thus provide the first estimates of the relative contribution of neutral and selective processes on variation of ant cuticular profile. Populations in migration-drift disequilibrium showed reduction of within-population variation for genetic markers as well as for cuticular profiles. In these populations, the cuticular profile became biased towards a limited number of high molecular weight molecules. Within- and among-population biochemical variation was explained by both genetic and social variation and by the spatial distribution of populations. We therefore propose that during range expansion of P. phylax, the composition of epicuticular compounds has been affected by a combination of neutral processes - genetic drift and spatially limited dispersal - and spatially varying selection, social organization and environmental effects.
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR 5175 CNRS, 34293 Montpellier, France. dalecky@supagro.inra.fr
authors.forename: Ambroise
authors.initials: A
authors.lastname: Dalecky
authors.forename: Marielle
authors.initials: M
authors.lastname: Renucci
authors.forename: Alain
authors.initials: A
authors.lastname: Tirard
authors.forename: Gabriel
authors.initials: G
authors.lastname: Debout
authors.forename: Maurice
authors.initials: M
authors.lastname: Roux
authors.forename: Finn
authors.initials: F
authors.lastname: Kjellberg
authors.forename: Erick
authors.initials: E
authors.lastname: Provost
mesh_terms: D025041:Animal Migration; D000818:Animals; D001000:Ants / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002163:Cameroon; D019143:Evolution, Molecular; D005260:Female; D040961:Genetic Drift; D005819:Genetic Markers; D014644:Genetic Variation; D008297:Male; D018895:Microsatellite Repeats; D012726:Sexual Behavior, Animal; D012919:Social Behavior; D013037:Spatial Behavior
chemical_list: D005819:Genetic Markers