Molecular Ecology (2008) 17, 4608-4618

J. Peccoud, C.C. Figueroa, A.X. Silva, C.C. Ramirez, L. Mieuzet, J. Bonhomme, S. Stoeckel, M. Plantegenest and J.-C. Simon (2008)
Host range expansion of an introduced insect pest through multiple colonizations of specialized clones
Molecular Ecology 17 (21), 4608-4618
Abstract: Asexuality confers demographic advantages to invasive taxa, but generally limits adaptive potential for colonizing of new habitats. Therefore, pre-existing adaptations and habitat tolerance are essential in the success of asexual invaders. We investigated these key factors of invasiveness by assessing reproductive modes and host-plant adaptations in the pea aphid, Acyrthosiphon pisum, a pest recently introduced into Chile. The pea aphid encompasses lineages differing in their reproductive mode, ranging from obligatory cyclical parthenogenesis to fully asexual reproduction. This species also shows variation in host use, with distinct biotypes specialized on different species of legumes as well as more polyphagous populations. In central Chile, microsatellite genotyping of pea aphids sampled on five crops and wild legumes revealed three main clonal genotypes, which showed striking associations with particular host plants rather than sampling locations. Phenotypic analyses confirmed their strong host specialization and demonstrated parthenogenesis as their sole reproductive mode. The genetic relatedness of these clonal genotypes with corresponding host-specialized populations from the Old World indicated that each clone descended from a particular Eurasian biotype, which involved at least three successful introduction events followed by spread on different crops. This study illustrates that multiple introductions of highly specialized clones, rather than local evolution in resource use and/or selection of generalist genotypes, can explain the demographic success of a strictly asexual invader.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Christian C. Figueroa

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
new introduction of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Acyrthosiphon pisum		Chile (continental)