Worker Bees’ Size Shrinking Due to Neonic Alternative, Study
January 20, 2014
Editor’s Note: The study “Impact of chronic exposure to a pyrethroid pesticide on bumblebees and interactions with a trypanosome,” by Gemma L. Baron, Nigel E. Raine and Mark J. F. Brown is available here. The authors note: “The vast majority of recent available data on the sublethal impacts of pesticides on bumblebees focuses on neonicotinoids, whilst other pesticide classes remain relatively understudied.”
To what extent has pyrethroid exposure been controlled for in studies of neonics?
From: University Herald
Worker Bees’ Size Shrinking Due to Pesticide Use, Study
By Stephen Adkins, UniversityHerald Reporter
Pyrethroid pesticide, a widely used insect repellent on flowering crops, shrinks bee size, according to a new study by Royal Holloway University of London. Researchers said that exposure to the pesticide hinders growth of worker bumblebees.
For the study, the researchers – Gemma Baron, Dr Nigel Raine and Professor Mark Brown from the School of Biological Sciences – exposed half of the colonies of bumblebees in their laboratory to the pesticide.
They observed the bees’ growth over a four month period including the number of queens and male bees produced, recorded their size and weighed them on micro-scales.
“We already know that larger bumblebees are more effective at foraging. 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,” Baron said in a press release.
This is the first study to look at the impact of pyrethroid pesticides on the lifecycle of bumblebees.
“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. 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,” Brown said.
Since the EU has slapped a two-year ban on three key neonicotinoid pesticides, the use of other pesticides, including pyrethroids, is likely to increase.
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