Signals of adaptation to agricultural stress in the genomes of two European bumblebees

Abstract

Human-induced environmental impacts on wildlife are widespread, causing major biodiversity losses. One major threat is agricultural intensification, typically characterised by large areas of monoculture, mechanical tillage, and the use of agrochemicals. Intensification leads to the fragmentation and loss of natural habitats, native vegetation, and nesting and breeding sites. Understanding the adaptability of insects to these changing environmental conditions is critical to predicting their survival. Bumblebees, key pollinators of wild and cultivated plants, are used as model species to assess insect adaptation to anthropogenic stressors. We investigated the effects of agricultural pressures on two common European bumblebees, Bombus pascuorum and B. lapidarius. Restriction-site Associated DNA Sequencing was used to identify loci under selective pressure across agricultural-natural gradients over 97 locations in Europe. 191 unique loci in B. pascuorum and 260 in B. lapidarius were identified as under selective pressure, and associated with agricultural stressors. Further investigation suggested several candidate proteins including several neurodevelopment, muscle, and detoxification proteins, but these have yet to be validated. These results provide insights into agriculture as a stressor for bumblebees, and signal for conservation action in light of ongoing anthropogenic changes.

Whole genome analyses reveal weak signatures of population structure and environmentally associated local adaptation in an important North American pollinator, the bumble bee Bombus vosnesenskii

“…For instance, in both data sets, we recovered genes that are involved with neuromuscular function such as LOC117231202 ( hemicentin‐1 ) in the EAA data set and LOC117234230 ( sema2a ) in the selective sweep data set. This overlap provides additional support for neural and neuromuscular development processes as targets of adaptation, which has been observed in other data sets (Hart et al, 2022; Heraghty et al, 2022; Jackson et al, 2020; Sadd et al, 2015; Sun et al, 2020). Another gene of interest that was detected was LOC117231198 ( sut1 , annotated as solute carrier family 2, facilitated glucose transporter member 3 in B. vosnesenskii ), which is involved in transmembrane sugar transport, and is intriguing given the importance of sugar as a fuel for nectar‐consuming bumble bees.…”

Selection despite low genetic diversity and high gene flow in a rapid island invasion of the bumblebee, Bombus terrestris

“…Precipitation can influence bee activity periods, where heavy rainfall coupled with increased wind speeds affect flight performance and energy expenditure (Lawson & Rands, 2019). The gene titin was also found to be selected for in other Bombus species, potentially as a response to agricultural stressors (Hart et al., 2022). Thus, these candidate loci may be involved in adaptation to novel environments in B. terrestris , where precipitation or other linked environmental factors might be drivers of selection.…”

“…The gene titin was also found to be selected for in other Bombus species, potentially as a response to agricultural stressors (Hart et al, 2022). Thus, these candidate loci may be involved in adaptation to novel environments in B. terrestris, where precipitation or other linked environmental factors might be drivers of selection.…”

“…Although gene flow has the potential to disrupt locally adapted genes, it may also promote adaptive potential by increasing genetic diversity in genetically impoverished populations (Garant et al, 2007). Previous studies have found evidence for local adaptation in native Bombus species in response to agricultural stressors (Hart et al, 2022). Colgan et al (2022) was under putative selection (Huml et al, 2021).…”