A genome-wide approach for uncovering evolutionary relationships of Australian Bactrocera species complexes (Diptera: Tephritidae)

Abstract

Australia and Southeast Asia are hotspots of global diversity in the fruit-fly genus Bactrocera. Although a great diversity of species has been long recognised, evolutionary relationships are poorly understood, largely because previous sequencing techniques have provided insufficient historical signal for phylogenetic reconstruction. Poorly understood biogeographic history in Bactrocera has prevented a deeper understanding of migratory patterns in this economically important pest group. Using representatives from Australia and Malaysia, we tested the utility of a genome-reduction approach that generates thousands of single-nucleotide polymorphisms for phylogenetic reconstructions. This approach has high utility for species identification because of the ease of sample addition over time, and the species-level specificity able to be achieved with the markers. These data have provided a strongly supported phylogenetic tree congruent with topologies generated using more intensive sequencing approaches. In addition, our results do not support taxonomic assignments to species complex for a number of species, such as B. endiandrae in the dorsalis complex, yet find a close relationship between B. pallida and the dorsalis species. Our data have further validated non-monophyletic evolution of male response to primary attractants. We also showed at least two diversification events between Australia and Southeast Asia, indicating trans-regional dispersal in important pest species.

Six years of fruit fly surveys in Bangladesh: a new species, 33 new country records and discovery of the highly invasive Bactrocera carambolae (Diptera, Tephritidae)

“…The genus Zeugodacus , of which a new species is described in this paper, is treated as separate from Bactrocera Macquart and Dacus Fabricius, based on recent molecular-based phylogenetic assessments (Krosch et al 2012; Virgilio et al 2015; Dupuis et al 2017; San Jose et al 2018a). Despite recent efforts to reassign species to subgenera (e.g., Hancock and Drew 2018 a, b), the understanding of higher relationships of species within Dacini is still in state of flux, and a number of traditionally recognized subgenera and species complexes (Drew and Romig 2013) are demonstrated to be polyphyletic groups of convenience defined on the basis of highly homoplastic morphological characters and male lure relations (e.g., Leblanc et al 2015b; San Jose et al 2018a; Catullo et al 2019). For this reason, we have not attempted to include subgenera in the country’s species list.…”

Biogeography, Speciation and Taxonomy within the genus Bactrocera Macquart with application to the Bactrocera dorsalis (Hendel) complex of fruit flies (Diptera: Tephritidae: Dacinae)

“…For practical identification reasons, species are placed within complexes on the basis of morphological similarity. Such groupings are not intended to reflect genetic relationships, a point not understood by Catullo et al (2019) in stating that B. endiandrae should not be placed in the dorsalis complex.…”