Distinguishing white-tailed bumblebees in the Netherlands: morphology, ecology and DNA-barcoding
White-tailed bumblebee species, Bombus cryptarum, B. lucorum, B. magnus and B. terrestris are known to be very similar in their morphological characters across the majority of their ranges. This hampers assessment of their status and trends because reliable identification is difficult. In this study, we use a combination of characters and methods to assess how ecologists and citizen scientists can reliably and quickly separate these four species occurring in the Netherlands. Bumblebees (queens,
... Bumblebees (queens, workers and males) were sampled from 10 locations across the Netherlands and specimens were identified based on COI sequence data. Next, the same specimens where scored for morphological traits. We show that a combination of easy to recognise characteristics can separate some specimens of the species depending on caste and sex. Bombus magnus males and queens and B. lucorum males were most reliably separated from the other species using morphological characters. Workers of all four species cannot be separated completely using morphological characters alone. This is the first time standard morphological characters and ecological data has been used to study the differences between the white-tailed bumblebees in the Netherlands. Based on our findings we need to conclude that the status of these bumblebee species in the Netherlands is uncertain due to possible misidentifications in the past and present. People who wish to work with these species should be careful in species identification based on morphology. Concise cover letter We attempt to answer the question if easily recognizable characteristics can be used by non-experts to reliably identify bumblebees of thelucorum complex and Bombus terrestris in the Netherlands.