Heatwaves lasting just a few days can leave wild bees permanently smaller and weaker, reducing their ability to pollinate crops and wild plants, according to new research by Polish scientists.
The study found that red mason bees (Osmia bicornis) exposed to extreme temperatures while developing as larvae emerged with smaller bodies and wings, flew more slowly, took flight less often and covered shorter distances throughout their lives.
The findings raise fresh concerns about the impact of increasingly frequent heatwaves on pollinators, which play a vital role in agriculture and healthy ecosystems.
Researchers from the Institute of Systematics and Evolution of Animals at the Polish Academy of Sciences and the Hugo Kołłątaj University of Agriculture in Kraków examined how moderate and extreme heatwaves forecast for Europe affect the development of red mason bees, one of the continent's most important wild pollinators of fruit crops and many flowering plants. The study was published in Proceedings of the Royal Society B.
"Although the period of extreme temperatures lasted only a few to a dozen or so days, its effects persisted throughout the insects' lives," said lead author Dr Agnieszka Gudowska of the Institute of Systematics and Evolution of Animals.
"Adult bees were smaller, had smaller wings, took flight less frequently, flew slower, and covered shorter distances. The strongest effects were observed in cases of extreme heatwaves lasting several days."
Gudowska said the reduced flight ability could make it harder for bees to find flowers, lowering pollination efficiency.
"The beginning of this summer alone has shown that heatwaves are becoming an increasingly frequent phenomenon in Poland as well," she said.
"As extreme thermal events become more frequent, such long-term morphological and functional deficits in pollinators may limit their mobility, foraging efficiency, and the provision of ecosystem services. In the long term, this could have implications for both ecosystem functioning and agriculture."
She said protecting and restoring diverse habitats that provide cooler microclimates—including woodlots, shrubs, unmown meadows and dead wood—could help reduce the impact of heatwaves on wild pollinators. Ensuring a continuous supply of flowering plants in agricultural and urban areas would also give heat-stressed insects easier access to food.
However, Gudowska stressed that tackling climate change remains the most effective long-term solution, warning that the growing frequency and intensity of heatwaves will continue to increase pressure on pollinator populations. (PAP)
PAP - Science in Poland
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