Resolving the species status of overlooked West‐Palaearctic bumblebees

Abstract

Multisource approaches in taxonomy gather different lines of evidence in order to draw strongly supported taxonomic conclusions and constitute the basis of integrative taxonomy. In the case of overlooked taxa with disjunct distributions for which sampling is more challenging, integrative approaches help to propose stable hypotheses at the species and subspecies levels. Here, based on genetic and semio‐chemical traits, we performed an integrative taxonomic analysis to evaluate species delimitation hypotheses within a monophyletic group of bumblebees (Hymenoptera, Apidae, Bombus) including the formerly recognised subgenera Eversmannibombus, Laesobombus and Mucidobombus which are now included in the subgenus Thoracobombus. Our results demonstrate the conspecificity of several polytypic taxa, and we formally recognise the subspecies Bombus laesus aliceae comb. nov. Cockerell, 1931, endemic to North Africa, based on its allopatry, unique mitochondrial haplotype and divergent cephalic labial gland secretions. This highlights the need to maintain studying polytypic complexes of bumblebee taxa for which phylogenetic relationships could be still entangled and eventually implement conservation strategies for taxonomically differentiated lineages.

Can biogeography help bumblebee conservation?

“…(Williams et al 2012b;Williams 2021). Some of the other subgenera have had only a few of the more problematic species-groups reviewed or new species described, including, e.g., Thoracobombus Dalla Torre, 1880 (Brasero et al 2021), Pyrobombus Dalla Torre, 1880 (Williams et al 2009b(Williams et al , 2014(Williams et al , 2022a(Williams et al , 2022cMartinet et al 2018b;Sheffield et al 2020;Potapov et al 2021;Williams 2022a), and Cullumanobombus Vogt, 1911(Williams et al 2012c. In contrast, some recent studies continue to give more emphasis to an interbreeding concept of species, for example in regarding male pheromones as decisive for recognising species (Martinet et al 2018a;Lecocq et al 2019), rather than regarding male pheromones as just one more source of information for integrative analyses (Williams et al 2019(Williams et al , 2020.…”

A revision of the Andrena (Hymenoptera: Andrenidae) fauna of Iran, with the description of 16 new species

“…mocsaryi Kriechbaumer, 1877, which vary in hair colour and are present in sympatry across much of Eastern Europe. Though varying in their hair colour, these taxa were recently found to belong to the same broad taxon (Brasero et al 2021).…”

A worthy conservation target? Revising the status of the rarest bumblebee of Europe

“…based on allopatry and colour pattern, Lecocq et al 2015); (ii) a low genetic differentiation accompanied with a dialectic semio-chemical signal (e.g. Brasero et al, 2020Brasero et al, , 2021; (iii) a significant genetic differentiation with a dialectic semio-chemical signal (Martinet et al, 2018, but see Williams et al, 2019. The present taxon reinigiellus falls in the first case where the taxon is isolated, presents tenuous but extant morphological and colour differences (Rasmont, 1983;Castro, 1988) and a distinct wing phenotype and a unique wing size/ITD ratio but shows no molecular differentiation based on our two other traits (COI and CLGS).…”

“…wing shape and size, colour pattern) or ecological traits (e.g. unique trophic association with a particular resource, divergence in semio-chemical signals to attract a conspecific mate) (Hawlitschek et al, 2012;Lecocq et al, 2015a;Martinet et al, 2019;Brasero et al, 2021;Lhomme et al, 2021). Our choice to formally recognise subspecies has the combined advantage of drawing attention to distinctive populations that vary in potentially adaptive traits and to prevent an artificial taxonomic inflation at the specific level (Isaac et al, 2004).…”