DNA Barcodes Suggest Cryptic Speciation in<i>Dasineura oxycoccana</i>(Diptera: Cecidomyiidae) on Cranberry,<i>Vaccinium macrocarpon</i>, and Blueberry,<i>V. corymbosum</i>

Abstract

Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae) from cranberry Vaccinium macrocarpon is similar morphologically to D. oxycoccana from blueberry V. corymbosum, but a recent study revealed that individuals from cranberry do not mate with those from blueberry. To seek genetic differences between D. oxycoccana from cranberry (common name cranberry tipworm) and from blueberry (common name blueberry gall midge), we compared a 559-bp region of the mitochondrial cytochrome oxidase I (COI) gene from 65 individuals. Analysis of the COI sequences based on general time reversible with gamma distribution (GTRG) distance model revealed 10.7–13.1% divergence between cranberry tipworm and blueberry gall midge, whereas little divergence was observed within cranberry tipworm (0– 1.2%) or blueberry gall midge (0–1.3%) sequences. In neighbour-joining analysis, conducted for species identification, blueberry gall midge sequences generated in this study clustered with known D. oxycoccana sequences from National Council of Biotechnology (NCBI), but the cranberry tipworm sequences grouped into a separate cluster. To identify and discriminate cranberry tipworm and blueberry gall midge, we developed diagnostic PCR primers based on COI sequence differences. In a duplex PCR assay, these primers successfully discriminated D. oxycoccana originating from cranberry or blueberry. The concordance between data from our genetic studies and data from mating experiments by Cook et al. (2011) suggests cryptic speciation in D. oxycoccana populations on cranberry and blueberry.