Bumblebees Can’t Taste Pesticides in Nectar: Alarming Consequences for Pollinators

Our recent understanding of bumblebees and their interaction with pesticides has taken a significant turn with new findings from a study conducted by the University of Oxford.

This research brings to light a crucial aspect of the foraging behaviour of these essential pollinators and reveals a gap in their ability to detect the presence of harmful chemicals in their environment.

This inability means they inadvertently consume these dangerous substances, significantly increasing their risk of harm. Bumblebees can differentiate between various sugary solutions but seem unable to detect pesticides.

To investigate this further, a team led by Dr Rachel Parkinson conducted a study focusing on the common bumblebee species Bombus terrestris. They used two approaches: electrophysiology to assess neuron responses and behavioural tests to observe feeding patterns.

Focusing on the Bombus terrestris species, the study lays the groundwork for further investigation into how these creatures unwittingly consume harmful substances due to their inability to taste pesticides.

By understanding this limitation in bumblebees’ sensory perception, we can work towards developing more effective conservation strategies to ensure their well-being and sustain their essential role as pollinators in our ecosystems.

Increased Exposure

The results were alarming: the bees showed no difference in neuron responses to sugar solutions with or without pesticides. They consumed both types equally, indicating a lack of detection mechanisms for common pesticides in their taste system.

We discovered that bumblebees cannot detect pesticides in nectar, even at potentially fatal concentrations. This concerning finding implies that bumblebees are unable to avoid consuming tainted nectar, significantly elevating their risk of harmful pesticide exposure.

In agricultural landscapes, this increased exposure can affect both wild plants and outdoor crops, as bees play a crucial role in pollination and require an abundance of pollen to thrive.

Bumblebees and pesticides

Bumblebees, such as the buff-tailed bumblebee, alongside honeybees, play a crucial role in pollination of agricultural crops. However, our pollinator friends face significant threats from neonicotinoid pesticides contaminating their nectar and pollen sources. We find that research on the bee’s ability to detect neonicotinoids yields inconsistent results, making it unclear whether they can avoid these harmful substances in their food sources. Fast action is needed to understand and mitigate the impact of pesticides on essential insect pollination.

Detecting Toxic Compounds

Through our research, we discovered that bumblebees possess a natural ability to differentiate between various sugar solutions found in nectar. Consequently, we explored whether this sense of taste could help bees identify and avoid pesticides. Our observations indicated that bumblebees can detect specific toxic compounds, such as quinine, owing to its bitter taste.

How the Research Was Conducted

We conducted our study by utilising two separate techniques to analyse bumblebees’ capability to detect pesticides, specifically neonicotinoid and sulfoximine. Our research focused on Bombus terrestris, a prevalent bumblebee species, and incorporated nectar from oilseed rape (Brassica napus) in our tests. Employing electrophysiology, we evaluated their responses, ensuring a comprehensive understanding of these important pollinators’ susceptibility to these harmful substances.

Bees’ Response When Tasting Pesticides

Through electrophysiology, we recorded neuron responses in bumblebees’ taste sensilla, which is similar to human tastebuds, on their mouthparts. This method helped us gauge the bees’ reactions to various tastes. Additionally, we observed the bees’ feeding behaviour by offering them sugar solutions with and without pesticides. Ultimately, these techniques allowed us to better understand the bumblebees’ ability to taste pesticides and whether these chemicals act as a deterrent.

Critical Insights into Bees and Pesticides

We discovered that bumblebees’ neurons did not show any difference in responses when consuming sugar solutions mixed with pesticides compared to sugar solutions alone. This suggests that their mouthparts lack the ability to detect common pesticides in nectar.

In addition, our behavioural tests revealed that bees consumed equal amounts of both pesticide-laced and pesticide-free solutions, even when the pesticide concentration posed a risk of harm. This highlights the negative effects of pesticides on pollinating insects, which might impact bee populations as they are unable to differentiate between contaminated and safe food sources in nature.

Why This Study Holds Importance

This study holds great importance in the realm of science, public concern, and health, as it highlights the inability of bumblebees to taste pesticides, a vital finding given the risk posed to bees by consuming contaminated nectar. As the researchers mentioned, these findings could pave the way for seeking a non-toxic compound that repels bees, allowing us to protect bees from harmful pesticide exposure on outdoor crops.

The findings also touch upon the idea of “bitter” taste avoidance using quinine. Bees exhibited an aversion to high concentrations of quinine-laced sugar solutions while not showing any reduction in intake of pesticide-infused ones. This suggests that bees have some ability to detect and react to specific bitter tastes.

Focusing on the protection of bees and their well-being is crucial, as they play a key role in pollination, resulting in a healthier ecosystem and agricultural system. By understanding the limitations in their ability to avoid harmful substances, we can work towards developing more sustainable practices to protect them and the environment.

Study Implications

Our findings underline the serious problem in the relationship between bees and pesticides. The bees’ inability to recognise and dodge nectar contaminated with pesticides endangers their health and jeopardises their irreplaceable role in pollinating crops. Research from the University of Oxford indicates potential knock-on negative impacts on colony fitness and crop yields.

We investigated pesticides that include neonicotinoids, such as imidacloprid, thiamethoxam, clothianidin, and the sulfoximine pesticide sulfoxaflor. Our study paves the way for future research and strategies to lessen the risks of pesticide use in agriculture, focusing on maintaining bee health and pollination services.

The in-depth results of this study are available in the journal eLife.


  1. Earth.com News ArticleBumblebees can’t taste lethal pesticides in nectar
  2. University of Oxford Study – Highlighted in the eLife journal.
  3. Dr. Rachel Parkinson’s Research – Leading the investigation into bees’ pesticide detection abilities.

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