Bucking the trend of pollinator decline: the population genetics of a range expanding bumblebee

No severe genetic bottleneck in a rapidly range-expanding bumblebee pollinator

“…Hence, whether colonization of the UK by B. hypnorum truly exemplifies the genetic paradox of invasion is uncertain. This suggestion is also consistent with the findings of a recent RAD-seq study that showed similar levels of genetic diversity and no evidence of structuring between six UK B. hypnorum populations and one in northern France [47].…”

“…Therefore, the allele number data do not support the UK B. hypnorum population having been founded in a single event by as few as two multiply-mated queens. Expected heterozygosity and allelic richness at microsatellite loci in the study B. hypnorum population (H e = 0.51, A R = 5.9) were both higher than values reported in Belgian and Estonian B. hypnorum populations for which comparable data exist (Belgium: H e = 0.37-0.39, A R = 1.94-2.03; Estonia: H e = 0.33, A R = 1.94) [55], while Huml et al [47] found similar sequence-level diversity between UK B. hypnorum populations and a French population. In addition, expected heterozygosity in the study B. hypnorum population was, on average, intermediate between values found by previous studies in common, established, and widespread European Bombus species and scarce, rangerestricted, and/or declining species (electronic supplementary material, table S8).…”

Co-benefits from tree planting in a typical English agricultural landscape: Comparing the relative effectiveness of hedgerows, agroforestry and woodland creation for improving crop pollination services

“…Ground-nesting bumblebees are already known to be more important pollinators of OSR and field beans than solitary bees (Garratt et al, 2014b;. Less is known about the relative importance of tree-nesting bumblebees in OSR or field bean pollination, but as they are known to be visitors of both crops (Hutchinson et al, 2021), their population is increasing in the UK (Huml et al, 2021) and they are likely to benefit from increased tree cover (Crowther et al, 2014), we also include them in this analysis. Image et al (2022) simulated bee abundance and visitation rates for two landcover scenarios for England: one in which AES-supported management in the year 2016 was present (AES_Present) and an alternative in which AES-supported management was absent (AES_Absent).…”

Bumblebees of the hypnorum-complex world-wide including two new near-cryptic species (Hymenoptera: Apidae)

“…Bombus hypnorum (in the previous broad sense) is of particular interest because it is one of the few bumblebee taxa to have increased substantially in its European distribution range without any deliberate introductions having been documented (Prŷs-Jones 2019; Huml et al 2021;Rasmont et al 2021).…”

“…Quantitative comparative analyses have the potential to allow us to understand more about such 'winners' and to better contrast them with the 'losers' that have shown range declines (Williams et al 2009a). During this century, the hypnorum-complex has expanded in range within Europe, for example establishing for the first time in Britain (Goulson & Williams 2001;Crowther et al 2014;Prŷs-Jones 2014;Huml et al 2021), in Ireland (O'Donnell 2018), and in Iceland (Prŷs-Jones et al 2016. There have been suggestions that these bees are associated, in some regions of Europe at least, especially with human activities within the forests (Løken 1973) or within tree-rich suburbs of towns (Rasmont et al 2021).…”