Population structure of Bactrocera dorsalis s.s., B. papayae and B. philippinensis (Diptera: Tephritidae) in southeast Asia: evidence for a single species hypothesis using mitochondrial DNA and wing-shape data

Abstract

BackgroundBactrocera dorsalis s.s. is a pestiferous tephritid fruit fly distributed from Pakistan to the Pacific, with the Thai/Malay peninsula its southern limit. Sister pest taxa, B. papayae and B. philippinensis, occur in the southeast Asian archipelago and the Philippines, respectively. The relationship among these species is unclear due to their high molecular and morphological similarity. This study analysed population structure of these three species within a southeast Asian biogeographical context to assess potential dispersal patterns and the validity of their current taxonomic status.ResultsGeometric morphometric results generated from 15 landmarks for wings of 169 flies revealed significant differences in wing shape between almost all sites following canonical variate analysis. For the combined data set there was a greater isolation-by-distance (IBD) effect under a ‘non-Euclidean’ scenario which used geographical distances within a biogeographical ‘Sundaland context’ (r2 = 0.772, P < 0.0001) as compared to a ‘Euclidean’ scenario for which direct geographic distances between sample sites was used (r2 = 0.217, P < 0.01). COI sequence data were obtained for 156 individuals and yielded 83 unique haplotypes with no correlation to current taxonomic designations via a minimum spanning network. beast analysis provided a root age and location of 540kya in northern Thailand, with migration of B. dorsalis s.l. into Malaysia 470kya and Sumatra 270kya. Two migration events into the Philippines are inferred. Sequence data revealed a weak but significant IBD effect under the ‘non-Euclidean’ scenario (r2 = 0.110, P < 0.05), with no historical migration evident between Taiwan and the Philippines. Results are consistent with those expected at the intra-specific level.ConclusionsBactrocera dorsalis s.s., B. papayae and B. philippinensis likely represent one species structured around the South China Sea, having migrated from northern Thailand into the southeast Asian archipelago and across into the Philippines. No migration is apparent between the Philippines and Taiwan. This information has implications for quarantine, trade and pest management.

Mating Compatibility Among Four Pest Members of the <I>Bactrocera dorsalis</I> Fruit Fly Species Complex (Diptera: Tephritidae)

“…We believe that in addition to previously reported differences between these species (e.g., pheromone composition), especially for B. carambolae, that behavioral variation (e.g., differences in mating location) contribute to the mating incompatibility observed here between B. carambolae and the remaining three species. While these data alone cannot be used to redeÞne species limits or to assert full sexual compatibility (because of the absence of full postzygotic testing; not completed in this study yet underway) and the inherent caveats of artiÞcial cage studies (Walter 2003), we consider our results closely parallel previous research suggesting that B. dorsalis, B. papayae, and B. philippinensis represent the same biological species (Medina et al 1998, Wee and Tan 2000b, Tan 2003, Krosch et al 2013, Schutze et al 2012. Such an outcome has signiÞcant implications not only for their taxonomic identities, but has consequences for pest management (especially for the SIT for which knowledge of species limits and mating compatibility are critical) and international trade.…”

The mitochondrial genome of the peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae): Complete DNA sequence, genome organization, and phylogenetic analysis with other tephritids using next generation DNA sequencing

“…Testing was done without atp6 due to high rate of evolution in study (N 0.5). Even the recent molecular evidence also suggests that B. papayae, B. philippinensis, B. invadens and B. dorsalis represent one species (Krosch et al, 2013;Schutze et al, 2012Schutze et al, , 2015Jose et al, 2013;Boykin et al, 2014) which has also been confirmed by the phylogeny based on PCGs and rRNAs of mitogenomes in the present study. Supplementary data to this article can be found online at http://dx.…”

Evidence of weak genetic structure and recent gene flow between Bactrocera dorsalis s.s. and B. papayae, across Southern Thailand and West Malaysia, supporting a single target pest for SIT applications

“…Similarly, the biological status of members of B. dorsalis complex - B. dorsalis s.s., B. papayae , and B. phillipinensis - has recently been analyzed using independent multiple approaches such as studying several genes of mitochondrial DNA, microsatellite markers, and mating competitiveness [13-16]. This evidence suggests that they are the same entity.…”