Less ‘buzz’ in bee’s brains; Wikinews interviews Dr Sally Williamson about pesticide effect on bees

Monday, April 1, 2013

Scientists at the UK’s Newcastle University have published their research into the effect of neonicotinoid chemicals on the brains of honeybees in the Journal of Experimental Biology. The findings determined that chemicals such as imidacloprid and coumaphos did impair bee learning and memory.

Wikinews interviewed Dr. Sally Williamson, who co-authored the findings with Dr. Geraldine Wright, about how they went about confirming their hypothesis regarding the effects of different pesticides on honeybees and their learning abilities.

The Wikinews Q&A can be read below:

((Wikinews)) What is your role at the Newcastle University? And are you the lead study? When and where did you publish your findings?

Dr. Sally Williamson: I am a research associate in the Institute of Neuroscience at Newcastle University, working in the laboratory of Dr. Geraldine Wright. The paper was co-authored by myself and Dr. Wright, and was published in the Journal of Experimental Biology last month.

((WN)) What did your research involve?

DSW: The research involved feeding the pesticide imidacloprid, and the mite treatment coumaphos, to honeybees, then carrying out a learning and memory experiment. The learning experiment relies on a phenomenon called the Proboscis Extension Reflex (PER) whereby the bee extends its proboscis (sticks out its tongue) to receive a meal when the antennae are touched with sugar solution. In the lab, we can blow a floral scent at the bee at the same time as delivering the sugar solution- soon, the bee learns to extend its proboscis in response to the scent, having learned that this particular scent indicates a sugar reward. We then tested the bees’ memory, by comparing the PER response to both the trained scent, and a different novel scent.

((WN)) What prompted your research into the effect of chemicals such as neonicotinoids and coumaphos with regards to the interference of insect’s ability to learn?

DSW: The target of the pesticide imidacloprid is an acetylcholine receptor which is found in brain regions associated with learning and remembering olfactory information. Coumaphos inhibits the breakdown of acetylcholine at these same synapses. Therefore, we predicted that both compounds would affect olfactory learning, and that the effects of both compounds delivered together would be additive.

((WN)) What conditions did you test your hypothesis under?

DSW: We had a control group of bees fed sugar solution alone, then we had a group fed sugar solution containing low levels of imidacloprid, a group fed sugar solution containing coumaphos, and a group of bees fed sugar solution containing both imidacloprid and coumaphos. The pesticides were present at very low levels, similar to those which might be present in the nectar of flowers treated with imidacloprid, or to the levels of coumaphos which might be in the pollen and honey stores of a coumaphos-treated hive.

((WN)) For how long have you been conducting your investigation?

DSW: The investigation was mainly carried out from June-September 2011, then the data analysis and interpretation was carried out during the winter. In bee research, most of the lab work is carried out in a summer season when the bees are flying, then we spend the winter doing statistical analysis and writing up our results.

((WN)) Was the outcome as you expected?

DSW: We found that imidacloprid and coumaphos both impaired learning, and that they did indeed have an additive effect on learning impairment when administered together. A rather surprising finding on the memory test results was, that the bees could not tell the training odour, and a novel odour, apart- they responded to both equally, not preferring the odour associated with the sugar reward over the other odour which should have no rewarding associations.

((WN)) Did you work alongside anyone else in your research? Was any part of the investigation most difficult?

DSW: I worked alongside Dr. Wright who is the head of our research group, and also alongside students and staff performing different bee experiments focused on bee nutrition. We also had close links with our collaborators Dr Chris Connelly and Dr Mary Palmer at Dundee University, who have recently published a study on actual bee brains, supplying data about what the same pesticides do to the neurons when actually applied directly to the brain areas of the bee involved in learning and memory. The main difficulty involved in our study was that it involved a 6-day experimental protocol, performed every week for several months, so it was quite intensive! Another difficulty of bee work is, it is very weather dependant- if it rains or is cold, the bees aren’t out foraging and the experiment has to be postponed until the weather improves.