Complex trait differentiation between host-populations of the pea aphid Acyrthosiphon pisum (Harris): implications for the evolution of ecological specialisation
Abstract:Variation in traits affecting preference for, and performance on, new habitats is a key factor in the initiation of ecological specialisation and adaptive speciation. However, habitat and resource use also involves other traits whose influence on ecological and genetic divergence remains poorly understood. In the present study, we investigated the extent of variation of life-history traits among sympatric populations of the pea aphid Acyrthosiphon pisum, which shows several host races that are specialised on various plants of the family Fabaceae plants and is an established model for ecological speciation. First, we assessed the community structure of microbial partners within host populations of the pea aphid. The effect of these microbes on host fitness is uncertain, although there is growing evidence that they may modulate various important adaptive traits of their host such as plant utilisation and resistance against natural enemies. Second, we performed a multivariate analysis on several ecologically relevant features of host populations recorded in the present and previous studies (including microbial composition, colour morph, reproductive mode, and male dispersal phenotype), enabling the identification of correlations between phenotypic traits. We discuss the ecological significance of these associations of traits in relation to the habitat characteristics of pea aphid populations, and their consequences for the evolution of ecological specialisation and sympatric speciation. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 718–727.
Document Type: Research Article
Affiliations: 1: Institut des Sciences de l'Evolution de Montpellier, UMR Université Montpellier II – Centre National de la Recherche Scientifique (UMR 5554) – F-34095 Montpellier Cedex 05 – France 2: INRA, UMR 1099 Biologie des Organismes et des Populations appliquée à la Protection des Plantes (BiO3P), BP 35327 Le Rheu, F-35653, France 3: Agrocampus Ouest, UMR 1099 Biologie des Organismes et des Populations appliquée à la Protection des Plantes (BiO3P), Rennes, F-35042, France
Publication date: 2009-08-01