2026-05-06 ノースカロライナ州立大学（NC State）
Photo of a bumble bee (B. impatiens) on a cucumber flower, taking during the study. Photo credit: Elsa Youngsteadt.
＜関連情報＞
- https://news.ncsu.edu/2026/05/higher-temperatures-bumble-bees/
- https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.70267
- https://royalsocietypublishing.org/rsbl/article/19/5/20220581/63322/Larger-pollen-loads-increase-risk-of-heat-stress
営巣行動は、社会性ミツバチ（Bombus spp.）の気候変動に対する脆弱性を左右する Nesting biology shapes climate vulnerability of social bees (Bombus spp.)
Francis R. Mullan, Nicholas S. Green, Elsa Youngsteadt, Kevin E. McCluney, Clint A. Penick
Journal of Animal Ecology Published: 27 April 2026
DOI:https://doi.org/10.1111/1365-2656.70267
Abstract
- Climate warming is a major driver of global pollinator declines, including social bees that live in large colonies and provide critical pollination services. Nesting biology plays a key role in determining a colony’s resilience to climate change, but its influence on colony performance has received little attention.
- We investigate how climate warming affects bumble bee foraging efficiency and thermoregulatory behaviours under mid-century and late-century climate projections. We measured ambient air and nest temperatures in simulated above-ground and below-ground nests, assessed temperature dependence of foraging activity and conducted controlled trials to quantify worker thermoregulatory behaviours (wing fanning and brood incubation).
- Contrary to predictions, our results show that warming will increase optimal foraging hours for bumble bees and reduce brood incubation needs, potentially improving foraging performance. However, extreme summer temperatures could greatly increase fanning demands, particularly for above-ground nests, which would divert workers from foraging and other essential colony tasks.
- Our findings highlight that above-ground-nesting bumble bees are particularly vulnerable to warming due to escalating thermoregulatory demands, which could lead to colony failure under extreme conditions. Conservation efforts should consider nesting environment as a critical factor in climate resilience strategies for bees and other animal species.
花粉の負荷量が多いと、採餌中のマルハナバチの熱ストレスのリスクが高まる Larger pollen loads increase risk of heat stress in foraging bumblebees
Malia Naumchik;Elsa Youngsteadt
Biology Letters Published:17 May 2023
DOI:https://doi.org/10.1098/rsbl.2022.0581
Abstract
Global declines in bumblebee populations are linked to climate change, but specific mechanisms imposing thermal stress on these species are poorly known. Here we examine the potential for heat stress in workers foraging for pollen, an essential resource for colony development. Laboratory studies have shown that pollen foraging causes increased thoracic temperatures (Tth) in bees, but this effect has not been examined in bumblebees nor in real-world foraging situations. We examine the effects of increasing pollen load size on Tth of Bombus impatiens workers in the field while accounting for body size and microclimate. We found that Tth increased by 0.07°C for every milligram of pollen carried (p = 0.007), resulting in a 2°C increase across the observed range of pollen load sizes. Bees carrying pollen were predicted to have a Tth 1.7–2.2°C hotter than those without pollen, suggesting that under certain conditions, pollen loads could cause B. impatiens workers to heat from a safe Tth to one within the range of their critical thermal limits that we measured (41.3°C to 48.4°C). Bumblebees likely adopt behavioural or physiological strategies to counteract the thermal stress induced by pollen transport, and these may limit their foraging opportunities as environmental temperatures continue to increase.
