Chronic pesticide exposure results in smaller bees: Study

Zee Media Bureau\Philaso G Kaping New Delhi: Pesticides are affecting the physical growth of bumblebees thereby putting the survival of their colonies at risk, according to a new study. Mark Brown, a Royal Holloway University of London professor of evolutionary ecology and conservation, along with with fellow university researchers Nigel Raine and Gemma Baron studied the impacts of chronic exposure to the pesticide pyrethroid, commonly used on flowering crops to prevent insect damage, on bumblebee at both the individual and colony level. The researchers monitored bee colonies for over four months in the laboratory, recording colony growth and reproductive output. They found that pesticide-treated colonies produced workers with a significantly lower body mass. "We already know that larger bumblebees are more effective at foraging," said Gemma Baron. "Our result, revealing that this pesticide causes bees to hatch out at a smaller size, is of concern as the size of workers produced in the field is likely to be a key component of colony success, with smaller bees being less efficient at collecting nectar and pollen from flowers." This is a cause for concern as bees account for 80 percent of plant pollination by insects, vital to global food production. Without them, many crops would be unable to bear fruit or would have to be pollinated by hand. "Bumblebees are essential to our food chain so it`s critical we understand how wild bees might be impacted by the chemicals we are putting into the environment," said Mark Brown. "We know we have to protect plants from insect damage but we need to find a balance and ensure we are not harming our bees in the process." The findings are published in the Journal of Applied Ecology.