[Pollinator] Pesticides an bee memory

[De Angelis, Patricia]

Recent article from
*Ecological Society of America*
30 August 2018
<https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.1940>
*Dispatches*
Pesticides and bee memory

Richard Kemeny

Pesticides are negatively affecting the memory and learning ability of
bees, according to a new study (*J Appl Ecol* 2018;
doi.org/10.1111/1365-2664.13193). Social bees must remember the location of
thousands of food sources and return to the hive, meaning that memory loss
could have major consequences for colony survival, with possible
ramifications for agriculture and food security.

A team at the Royal Holloway University of London (Egham, UK) conducted a
meta‐analysis covering 23 papers, spanning almost a decade. The analysis
focused on studies using a common test for learning and memory in bees, in
which they learn to associate an unknown scent with a sucrose reward. The
researchers wanted to determine the effects of field‐realistic doses – a
contentious term, which they defined after consulting various recent
sources in the scientific literature. They also distinguished between acute
(one dose) and chronic (repeated doses over a period of days) exposure to
insecticides.

Combining data from across the studies showed significant impacts in both
learning and memory, even after just one brief encounter. “This occurs even
at the low levels of pesticides that bees would routinely encounter in the
field”, says lead author Harry Siviter. Long‐term exposure had additional
impacts on memory.

“Our findings highlight the need for policy makers and regulators to
increasingly consider the sublethal impacts of insecticides on important
pollinators such as bees”, Siviter continues. The research also exposes key
knowledge gaps. “Especially relevant is the scarcity of studies on the most
sensitive life stage of bees – the larvae”, explains Edward Mitchell,
a professor at the Institute of Biology, University of Neuchâtel
(Neuchâtel, Switzerland).

Earlier this year, the European Union voted in favor of a near‐total ban on
neonicotinoids – the most widely used insecticide – which is expected to
come into force in the coming months. But crucially, the team found no
difference between the impact of these and other pesticides on learning and
memory. “We should seriously question the idea that any pesticide can be
deemed safe for bees and other pollinators”, says Mitchell. “The question
here of course is sustainability in the very long term, and the
conservation of viable populations of pollinators.”
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