Retracing an insect pest invasion route

Next Monday, Emilie will present a paper presenting a study aiming to search for the most likely invasion route of an insect pest species: the aphid Myzus persicae nicotianae. They used seven microsatellites and various methods combining traditional (F-statistics, genetic diversity parameters), Bayesian-based (Structure) and coalescent-based (DiyABC) approaches. These methods helped them first to identify the genetic subdivisions of the species between the potential sources in Europe and North America and the newly colonized areas (South America). Then, the program DiyABC was used to test different colonization scenarios. Thanks Emilie.

From Zepeda-Paulo FA, Simon JC, Ramirez CC, Fuentes-Contreras E, Margaritopoulos JT, Wilson ACC, Sorenson CE, Briones LM, Azevedo R, Ohashi DV, Lacroix C, Glais L, Figueroa CC (2010) Molecular Ecology 19, 4738–4752

Title: The invasion route for an insect pest species: the tobacco aphid in the New World

Abstract

Background. Biological invasions are rapid evolutionary events in which populations are usually subject to a founder event during introduction followed by rapid adaptation to the new environment. Molecular tools and Bayesian approaches have shown their utility in exploring different evolutionary scenarios regarding the invasion routes of introduced species.

Aims. We examined the situation for the tobacco aphid, Myzus persicae nicotianae, a recently introduced aphid species in Chile. Using seven microsatellite loci and approximate Bayesian computation, we studied populations of the tobacco aphid sampled from several American and European countries, identifying the most likely source populations and tracking the route of introduction to Chile.

Major results and conclusions. Our population genetic data are consistent with available historical information, pointing to an introduction route of the tobacco aphid from Europe and ⁄ or from other putative populations (e.g. Asia) with subsequent introduction through North America to South America. Evidence of multiple introductions to North America from different genetic pools, with successive loss of genetic diversity from Europe towards North America and a strong bottleneck during the southward introduction to South America, was also found. Additionally, we examined the special case of a widespread multilocus genotype that was found in all American countries examined. This case provides further evidence for the existence of highly successful genotypes or ‘superclones’ in asexually reproducing organisms.