Genetical Research



Microsatellites reveal extensive geographical, ecological and genetic contacts between invasive and indigenous whitefly biotypes in an insular environment


H. DELATTE a1a4c1, P. DAVID a2, M. GRANIER a3, J. M. LETT a1, R. GOLDBACH a4, M. PETERSCHMITT a3 and B. REYNAUD a1
a1 CIRAD-UMR PVBMT-Université de la Réunion, Pôle de Protection des Plantes Ligne Paradis, 97410 Saint Pierre, La Réunion, France
a2 CEFE-CNRS, UMR 5175, 1919 Route de Mende, 34293 Montpellier Cedex 05, France
a3 CIRAD, UMR BGPI, TA 41/K, 34398 Montpellier, Cedex 5, France
a4 Wageningen University, Binnenhaven 11, 6709 PD Wageningen, The Netherlands

Article author query
delatte h   [PubMed][Google Scholar] 
david p   [PubMed][Google Scholar] 
granier m   [PubMed][Google Scholar] 
lett jm   [PubMed][Google Scholar] 
goldbach r   [PubMed][Google Scholar] 
peterschmitt m   [PubMed][Google Scholar] 
reynaud b   [PubMed][Google Scholar] 

Abstract

Human-mediated bioinvasions provide the opportunity to study the early stages of contact between formerly allopatric, divergent populations of a species. However, when invasive and resident populations are morphologically similar, it may be very difficult to assess their distribution in the field, as well as the extent of ecological overlap and genetic exchanges between invasive and resident populations. We here illustrate the use of data obtained from a set of eight microsatellite markers together with Bayesian clustering methods to document invasions in a group of major tropical pests, Bemisia tabaci, which comprises several morphologically indistinguishable biotypes with different agronomic impacts. We focus on the island of La Réunion, where an invasive biotype (B) has recently been introduced and now interacts with the resident biotype (Ms). The temporal and spatial distribution, host-plant range and genetic structure of both biotypes are investigated. We showed (i) that, without prior information, clustering methods separate two groups of individuals that can safely be identified as the B and Ms biotypes; (ii) that the B biotype has invaded all regions of the island, and showed no signs of genetic founder effect relative to the Ms biotype; (iii) that the B and Ms biotypes coexist in sympatry throughout most of their geographical ranges, although they tend to segregate into different host plants; and finally (iv) that asymmetrical and locus-specific introgression occurs between the two biotypes when they are in syntopy.

(Published Online May 19 2006)
(Received January 13 2006)
(Reviewed February 5 2006)


Correspondence:
c1 CIRAD-UMR PVBMT Pôle de Protection des Plantes Ligne Paradis, 97410 Saint Pierre, La Réunion, France. Tel: +262 (262) 499235. Fax: +262 (262) 499293. e-mail: delatte@cirad.fr


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