Low Oxygen May Hinder Insects' Upslope Migration

Scientists warn that the combined effects of lower oxygen and reduced air pressure at higher elevations could impede insects’ ability to shift upslope in response to climate warming, potentially jeopardising the ecosystem services they deliver, such as pollination. A recent review published in *Functional Ecology* synthesises evidence from a range of studies that demonstrate insects’ physiological limits to hypoxic and low‑pressure environments, which become increasingly pronounced as they move to higher altitudes.

The review highlights that many insect species rely on oxygen‑dependent flight muscles and thermoregulation mechanisms that are finely tuned to the atmospheric conditions of their native elevations. When temperatures rise, insects traditionally migrate upward to stay within their optimal thermal niche. However, the diminished oxygen availability and thinner air at those elevations can constrain flight performance and metabolic rates, effectively creating a “physiological barrier” that restricts further upslope movement. This limitation could reduce pollinator abundance and diversity in mountain ecosystems, with cascading effects on plant reproduction and food webs.

If insects cannot reach the higher, cooler habitats they need, the consequences for pollination services could be significant. Reduced pollinator presence may lower fruit set and seed production in alpine flora, altering species composition and diminishing biodiversity. The review calls for more research into how climate change and atmospheric physics interact to shape insect distribution, and for conservation strategies that consider these physiological constraints when protecting pollinator‑dependent ecosystems.