Pesticides are still reducing bee numbers despite EU regulation

30 Nov 2023

Image: © Laura Pashkevich/

Trinity College Dublin was part of a comprehensive study that found bee populations in Europe thrive in environments that use fewer pesticides.

A new European study has shed light on how existing regulation of pesticide use in the continent is not enough to curb its negative effects on bees and other pollinating species.

Spanning 106 sites across eight countries in Europe, a study published in Nature yesterday (29 November) shows that despite having some of the toughest regulation in the world, Europe still has a pesticide problem that is negatively affecting non-target organisms such as bees.

Bumblebee colonies exposed to pesticides in Europe, the study found, saw significant reductions in total colony production (the number of cocoons), maximum colony weight and the number of news queens – crucial to the survival and expansion of bee populations.

Bees are the most potent pollinators on the planet. According to experts at the Food and Agriculture Organisation of the United Nations, about a third of the world’s food production depends on bees.

“When you step outside the laboratory, a challenge of ecotoxicology is to capture the effect of real-world practices at organism-relevant scales,” said Dr Charlie Nicholson, co-lead author and postdoctoral researcher at Lund University in Sweden.

“With the largest experimental field deployment of any pollinator, we see that bumblebees encounter multiple pesticides in agricultural landscapes, resulting in fewer offspring. On top of this, pesticides do more harm in landscapes with less habitat.”

Dr Jessica Knapp, co-lead author of the paper and an assistant professor of botany at Trinity College Dublin (TCD), said that data from the study also show how bumblebees perform when we use less pesticides.

“These ‘healthier’ colonies that experience less pesticide risk help us generate a baseline to show that 60pc of our bumblebee colonies would fail proposed pollinator protection goals,” she explained.

“Our findings show that the current assumption of pesticide regulation – that chemicals which individually pass laboratory tests and semi-field trials and are considered environmentally benign – fails to safeguard bees and potentially other pollinators that support agricultural production and wild plant pollination.”

The study forms a key output of PoshBee, a European project including TCD seeking to monitor and improve bee health. Its findings support the need for sustainability goals to reduce pesticide use and risk – a vital part of the European Farm to Fork strategy.

“This work was possible because of the collaboration and dedication of the transdisciplinary field teams in each country and the partnership with the labs that conducted the common analyses,” said Prof Jane Stout of TCD, co-ordinator of the European field experiment.

“Researchers, beekeepers and farmers worked together to implement common protocols to collect these unique data. Similar collaborative approaches will be needed if we are to turn the tide and offer the far greater protection that pollinators need.”

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Vish Gain is a journalist with Silicon Republic