Unveiling cryptic species of the bumblebee subgenus<i>Bombus s. str.</i>worldwide with COI barcodes (Hymenoptera: Apidae)

Abstract

Bumblebees of the subgenus Bombus s. str. dominate (or used to dominate) many north temperate pollinator assemblages&#13;\nand include most of the commercial bumblebee pollinator species. Several species are now in serious decline, so&#13;\nconservationists need to know precisely which ones are involved. The problem is that many Bombus s. str. species are&#13;\ncryptic, so that species identification from morphology may be impossible for some individuals and is frequently misleading&#13;\naccording to recent molecular studies. This is the first review of the entire subgenus to: (1) avoid fixed a priori assumptions&#13;\nconcerning the limits of the problematic species; and (2) sample multiple sites from across the entire geographic ranges of&#13;\nall of the principal named taxa worldwide; and (3) fit an explicit model for how characters change within an evolutionary&#13;\nframework; and (4) apply explicit and consistent criteria within this evolutionary framework for recognising species. We&#13;\nanalyse easily-obtained DNA (COI-barcode) data for 559 sequences from 279 localities in 33 countries using general mixed&#13;\nYule-coalescent (GMYC) models, assuming only the morphologically distinctive species B. affinis Cresson, B. franklini&#13;\n(Frison), B. ignitus Smith and B. tunicatus Smith, and then recognise other comparable COI-barcode groups as putative&#13;\nspecies. These species correspond to modified concepts of the taxa B. cryptarum (Fabricius), B. hypocrita P´erez, B.&#13;\njacobsoni Skorikov, B. lantschouensis Vogt n. stat., B. longipennis Friese, B. lucorum (Linnaeus), B. magnus Vogt, B.&#13;\nminshanensis Bischoff n. stat., B. occidentalis Greene, B. patagiatus Nylander, B. sporadicus Nylander, B. terrestris&#13;\n(Linnaeus) and B. terricola Kirby (a total of 17 species). Seven lectotypes are designated. Our results allow us for the first&#13;\ntime to diagnose all of the putative species throughout their global ranges and to map the extent of these geographic ranges.