Do diesel exhaust particles in pollen affect colony founding in the bumble bee Bombus terrestris?

The global insect decline threatens ecosystem functioning because insects provide many essential services, such as pollination or nutrient cycling. Pollution is one of the main drivers of insect decline besides land-use change, global warming, and invasive species. Airborne particulate matter, such as diesel exhaust particles, is ubiquitous in the environment. Their effects on insects are still largely unknown. We provided queens and workers of the bumble bee Bombus terrestris with pollen spiked with diesel exhaust particles at the early colony founding stage and compared the colony development to control colonies. After 10 weeks, we investigated individual and colony-level life history traits. We did not see any effects of pollen spiked with diesel exhaust particles on worker count, brood count, worker size and relative fat body weight. These results indicate no harmful effects of diesel exhaust particles on colony founding in B. terrestris in our single-stressor setup. Our novel approach adds to the understanding of the role that airborne particulate matter plays in the global insect decline and we are looking forward to seeing similar studies with other species and additional stressors, such as heat stress or food shortages.