Host-associated genetic differentiation in Thrips tabaci (Insecta; Thysanoptera), as determined from mtDNA sequence data.
We tested for host-associated genetic differentiation in 22 populations of Thrips tabaci collected from tobacco and leek, respectively. Clustering analyses and haplotype networks based on sequence variation at a fragment of the mitochondrial cytochrome oxidase I gene yielded three major evolutionary lineages; two were clearly associated with leek and the third with tobacco. These genetic findings corroborated recent experimental observations on the heterogeneity of T. tabaci populations with regard to host-plant preference and their capacity to be vectors for tomato spotted wilt virus. Estimated divergence times suggested an ancient divergence of these lineages dating back to the Miocene 28-21 million years ago. F(ST) values between these lineages ranged between 0.824 and 0.954 (P<0.001 for all comparisons), and sequence divergences ranged between 4 and 11%. Given these findings and by the standards of genetic and ecological differentiation in other published species groups, T. tabaci must be considered a complex of cryptic (sub)species.
Brunner
P C
PC
Agroscope FAW Wädenswil, Swiss Federal Research Station for Horticulture, PO Box 185, Wädenswil CH-8820, Switzerland. patrickcbrunner@netscape.net
Chatzivassiliou
E K
EK
Katis
N I
NI
Frey
J E
JE
D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics; D006239:Haplotypes; D007313:Insecta / Q000235:genetics*; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D019697:Onions / Q000469:parasitology; D014026:Nicotiana / Q000469:parasitology
D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV