Topic: Environment
Dead bumblebees are being spotted on pavements in summer months. The cause is a combination of weather and human activities.
You may have noticed bodies of dead bumblebees lying across pavements near you in the summer months.
There are several reasons for this, some related to the weather and others due to human actions. Bumblebees live in colonies with short-lived workers that die off quickly. To prevent disease from spreading through the colony, healthy young workers bring out their dead and move them far away.
Another factor is the extreme heat. The warmest June on record in England (and the second hottest for the whole UK) was in 2026, and high temperatures are expected this summer. Thermal stress in bees is caused by this kind of extreme heat. Prolonged heat exposure can alter development and threaten long-term population stability.
Heatwaves also severely disrupt reproduction, flight capacity, and ability to forage. Social insects like bees rely on cooling behavior, such as fanning their wings when it gets too hot, but there are limits to how effective this is in extreme heat.
Bee deaths can also be caused by pesticide and herbicide use. These chemicals affect the fitness of bees, causing them to die off directly or remove important plants that they rely on for food, leading to starvation.
Dandelions, for example, are a crucial nectar source for bees but are often controlled with herbicides. Pesticide use is one of the historical key causes for loss of bees. The EU and UK have banned the most harmful neonicotinoids, but pesticides are still routinely used, causing harm to pollinators.
Insecticides like organophosphates, synthetic pyrethroids, and phenylpyrazoles can cause paralysis and death in insects or disrupt their ability to navigate. Habitat loss is another key issue for bees, with land use changing for housing developments, intensive agriculture, and other human structures.
Climate change is causing problems too. Phenological mismatch occurs when two organisms that depend on each other appear at the wrong time. With a changing climate, this is happening more often. Plants may flower before bees arrive or vice versa, which can be disastrous for both flowers and bees.
Insects are the most diverse and abundant group of animals on the planet but are also the most threatened. We're losing our bees at an alarming rate. In Europe, the number of wild bee species considered at risk of extinction has more than doubled from 77 in 2014 to at least 172 today (around 10% of assessed species).
However, we really need them. They provide essential ecosystem services like decomposition, pest control, food for other animals, and keeping our systems clean and tidy.
One such service is directly important for us: pollination. Bees disproportionately carry out this role, which is crucial for many crops.
Why It Matters
This matters because bees are essential for pollinating plants that provide food for humans. Losing them can have significant impacts on our food supply and ecosystem health.
Key Facts
- Bumblebees live in colonies with short-lived workers (4-6 weeks).
- The warmest June on record in England was in 2026, contributing to thermal stress in bees.
- Pesticide and herbicide use can directly harm bees or remove important plants they rely on for food.
- Habitat loss is another key issue for bees, with land use changing for human structures.
- Climate change is causing phenological mismatch between plants and bees.
Key Terms
- Neonicotinoids
- A type of pesticide that can harm pollinators.
- Phenological mismatch
- When two organisms dependent on each other appear at the wrong time due to climate change.
Implications
This matters because bees are essential for pollinating plants that provide food for humans. Losing them can have significant impacts on our food supply and ecosystem health.
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