Cambridge research shows bumblebees risk higher exposure to heavy metals than honeybees
The findings highlight differences in accumulation despite shared environments
Recent research from the University of Cambridge reveals that bumblebees collect significantly higher levels of toxic heavy metals compared to honeybees, even when foraging in the same environment. Exposure to these metals can adversely impact bees' foraging capabilities and reproductive success.
This metal pollution is often concentrated near industrial centres and towns, but it can also spread to rural areas through air, sewage sludge, agrochemicals, and fertilisers, making it a widespread issue.
Differences in Bee Species
While honeybees have traditionally been used to assess metal contamination in polluted areas, the study published in Ecological Entomology shows variation in how different bee species accumulate heavy metals. Bumblebees appear particularly vulnerable.
Researchers at Cambridge collected pollen samples and measured concentrations of toxic metals like arsenic, cadmium, and lead in pollen and bee bodies from apiaries in Cambridgeshire, an area with relatively low soil metal contamination. Despite foraging in the same landscapes, bumblebees accumulated up to seven times the level of heavy metals in their pollen compared to honeybees.
Possible Causes of Vulnerability
Dr. Sarah Scott, who conducted the research, noted differences likely stem from a mix of foraging behaviour and bee physiology. Honeybee colonies are larger and nest above ground, allowing them to cover wider areas, whereas bumblebees nest underground and travel shorter distances, making them more susceptible to local contamination.
Additionally, bumblebees' hairy bodies and tendency to collect less pollen from fewer sources mean they pick up more airborne particles containing metals.
Professor Lynn Dicks emphasised that even in typically safe rural areas, bees can still gather toxic metals. With bumblebee colonies having fewer workers, the loss of individuals significantly affects colony function.
Dr. Scott encouraged planting flowers to support bees, despite contamination risks, stressing the importance of ensuring bees have access to food.
The Royal Society funded the research, with Professor Dicks also serving as a Fellow at Selwyn College, University of Cambridge.