(Walker), a major invasive pest worldwide, was first described in
Fujian (China) in 1849 and has dispersed to tropical and subtropical
Asia and the South Pacific region.
Few data are available on its colonization history and expansion
This pilot study attempted to reconstruct the colonization history and
pathways of this pest in China and neighboring Southeast Asian countries
based on mitochondrial DNA.
Results of the study showed six genetic groups corresponding to
geographical characteristics, although the pattern was relatively weak.
Homogeneous genetic patterns were observed within southern and central
China, and northern Vietnam.
Continuous colonization from the coast of southern China to inland
regions of China and northern Vietnam was suggested.
Strong genetic structure was observed in western China, Thailand, and
The isolation of four of the six groups was most probably attributable
to major topographical barriers of western China.
Yunnan acted as a contact zone of B. tau in China and neighboring Southeast Asia.
The absence of isolation by distance and the overall low phylogeographic structure of B. tau suggested that long distance dispersal events and human activities could play a major role in the colonization and expansion patterns of B. tau.
By analyzing the genetic diversity, gene flow, haplotype phylogeny, and
demographic history of 23 fly populations, we hypothesized that B. tau
could have been introduced long ago in southern China, from which it
further expanded or that southern China could correspond to the native
range of this species.