Bombus (Melanobombus) bisiculus Lecocq, Biella, Martinet & Rasmont, 2019

Risch, Stephan, Roberts, Stuart P. M., Smit, Jan, Wood, Thomas J., Michez, Denis & Reverté, Sara, 2023, The new annotated checklist of the wild bees of Europe (Hymenoptera: Anthophila), Zootaxa 5327 (1), pp. 1-147 : 29-30

Bombus (Melanobombus) bisiculus Lecocq, Biella, Martinet & Rasmont, 2019

Bombus (Melanobombus) bisiculus Lecocq, Biella, Martinet & Rasmont, 2019: 7 . Holotype ♁; Italy: Sicily, Isnello (UMONS).

Individuals of the taxon described recently with the name Bombus bisiculus have been recorded traditionally as B. lapidarius decipiens Pérez, 1879 , because individuals of the new taxon share a yellow-banded colour pattern that has been given by some the status of a subspecies within B. lapidarius (Linnaeus, 1758) . But based on its divergence from Bombus lapidarius in northern Europe in COI barcodes and CLGS (cephalic labial gland secretions, believed to function as sex-specific pheromones in bumblebees), Lecocq et al. (2019) described the new taxon from southern Italy and Sicily as a separate species, B. bisiculus Lecocq, Biella, Martinet & Rasmont, 2019 (the name decipiens Pérez was applied originally to yellow-banded individuals of B. lapidarius from the Pyrenees and the Iberian Peninsula).

In a revision of the Melanobombus bumblebees world-wide, Williams et al. (2020) noted from a re-analysis of COI barcodes based in part on sequences provided by Lecocq et al. (2015), that some individuals (‘ lapidarius SE Europe’) were grouped in the tree together with the new taxon Bombus bisiculus . This group of individuals was not explicitly reported or discussed by Lecocq et al. (2019) when they formally described B. bisiculus . These SE Europe sequences came from unbanded specimens from Slovakia, the Czech Republic, Serbia, Bulgaria, and Hungary that are phenotypically identical to the typical B. lapidarius (Linnaeus, 1758) , not to the yellow-banded taxon bisiculus of Lecocq et al. (2019).

More significantly, Williams et al. (2020) highlighted that the SE Europe samples also produce CLGS mixtures (as reported by Lecocq et al. 2015), that are typical of B. lapidarius , not of B. bisiculus . Williams et al. (2020) therefore suggested that the definition of Bombus bisiculus by Lecocq et al. (2019) as a yellow-banded bumblebee species diverging in both COI barcodes and CLGS from B. lapidarius appears to be contradicted by the dataset of Lecocq et al. (2015) when the whole of Europe is considered. Williams et al. (2020) therefore concluded that there is disagreement between the two independent lines of evidence (COI and CLGS) from Lecocq et al. (2013, 2015, 2019), not the corroboration that would be required to support species status for the taxon bisiculus : the SE Europe bees have the COI of bisiculus but the CLGS of lapidarius .

In the absence of corroboration between COI and CLGS (a required combination for deserving a species status following Lecocq et al. 2013, 2015, 2019), we here consider the taxon bisiculus as a subspecies of B. lapidarius . Further genetic sequencing and semio-chemical data from Eastern Europe and the Balkans are required to understand more in detail the evolutionary history of these lineages.

Distribution. Southern Italy. Records from Bulgaria, the Czech Republic, Hungary, Serbia, and Slovakia need confirmation.

Taxonomic changes