Too strict or too loose? Integrative taxonomic assessment of Bombus lapidarius complex (Hymenoptera: Apidae)

Abstract

The latest progress of the taxonomy is the use of integrative approach for species delimitation based on a multisource dataset. However, the taxonomic decision that should be made when convergence between the different lines of evidence is not observed remains debated. Here, we investigate the consequences of the application of an ‘integration by cumulation’ approach on the taxonomic statuses within the Bombus lapidarius complex when using an integrative taxonomic framework (i.e. nuclear and mitochondrial markers along with reproductive traits) compared with a strict ‘integration by congruence’ method. Our results show similar taxonomic conclusions whatever the decision‐making approach used except for one taxon. According to the differentiation observed in our integrative taxonomic framework, recent divergence time and other field observations for this taxon, we assume that a too strict decision‐making method could fail to detect recently diverged species. This is exemplified by the new species Bombus bisiculus sp. n. occurring in South Italy and Sicily.

Widespread polytypic species or complexes of local species? Revising bumblebees of the subgenus Melanobombus world-wide (Hymenoptera, Apidae, Bombus)

“…Applying genetic methods has led to a new wave of 'splitting' of bumblebee species, as genetically distinct (but sometimes morphologically cryptic or near-cryptic) populations within the broader morphologicallydiagnosed taxon complexes have become interpreted as separate species (e.g., Bertsch et al 2005;Williams et al 2011Williams et al , 2012aWilliams et al , 2015bWilliams et al , 2016Ratnasingham & Hebert 2013;Lecocq et al 2014;Potapov et al 2017;Martinet et al 2018b). This has recently included proposing one new species within the subgenus Melanobombus (Lecocq et al 2013(Lecocq et al , 2015(Lecocq et al , 2019.…”

“…It was encouraged particularly because studies focussing on genetic evidence have tended to recognise more species than those considering morphology alone, so that some form of check on a single approach or resolution among multiple approaches was desired. Integrative assessment has been applied increasingly in studies revising bumblebee species (Bertsch et al 2004(Bertsch et al , 2005Williams et al 2011Williams et al , 2012aWilliams et al , 2015bWilliams et al , 2016Lecocq et al 2013Lecocq et al , 2014Lecocq et al , 2015Lecocq et al , 2019Potapov et al 2017;Martinet et al 2018b).…”

“…Accepting this conflict may make it more likely that recently-diverged species are recognised, although without care this approach could over-estimate the numbers of species (Padial et al 2010). The pros and cons of the application of the different forms of integrative assessment to bumblebees continue to be discussed (Martinet et al 2018a;Lecocq et al 2019;Williams et al 2019).…”

“…str., decipiens Pérez, 1890, and atlanticus Benoist, 1928 (Fig. 9), whereas the second includes the taxon bisiculus Lecocq et al, 2019. However, the second coalescent group also includes bees that are typical lapidarius s. str. in their morphology and CLGS from south-eastern Europe (Lecocq et al 2019) and so does not correspond to Lecocq et al's taxon bisiculus, which forms just a part of this group.…”

“…The male mate-searching behaviour is expected to resemble the patrolling of B. lapidarius. Vogt ( , 1911, Reinig (1935), and Lecocq et al (2015Lecocq et al ( , 2019 considered the taxon decipiens (thoracic dorsum with yellow bands) to be conspecific with the taxon lapidarius s. str. (thoracic dorsum black) as divergent regional colour patterns within a polytypic species.…”