Social Interaction Shields Honeybees From Heat
Recent experiments from Michigan State University reveal that honeybees cope much better with high temperatures when they are surrounded by nestmates. When solitary workers were exposed to 40 °C for an hour, their levels of the juvenile hormone (JH) – a key stress indicator – skyrocketed. In contrast, bees kept in groups of twenty‑five displayed a remarkably stable hormone profile, suggesting that the presence of companions blunts the physiological impact of scorching conditions.
The Role of Juvenile Hormone in Adult Bees
Although juvenile hormone is best known for steering insect development, adult honeybees use it to regulate behavior and task allocation. Young workers caring for larvae typically maintain low JH concentrations, whereas foragers venturing outside the hive exhibit higher levels. Thus, fluctuations in this hormone serve as a window into a bee’s internal state and its response to external challenges.
Testing the Power of Chemical Communication
To determine whether the protective effect stemmed solely from physical proximity or also from chemical cues, researchers turned their attention to ethyl oleate – a pheromone released by foragers during food collection. When solitary bees in hot bottles were treated with a modest dose of ethyl oleate, their hormone spikes were almost completely suppressed, mirroring the response of bees inside a crowd. This finding implies that the shared scent of colony members can convey a calming signal that mitigates heat‑induced stress.
Separating Heat from Loneliness
The team also repeated the trial at a milder 34.5 °C, a temperature commonly found inside a well‑ventilated hive. Under these conditions, no meaningful difference emerged between isolated and grouped individuals, confirming that the dramatic JH surge occurs only when heat and social isolation combine.
Implications for a Warming World
As climate change drives more frequent and intense heat waves, the resilience of pollinator populations becomes a pressing concern. This study suggests that the collective nature of bee colonies may act as a thermoregulatory buffer, helping entire hives endure rising temperatures better than previously assumed. However, the exact mechanism by which ethyl oleate exerts its “cooling” influence remains a mystery, opening new avenues for research into how insects use pheromonal networks to manage environmental stress.
Understanding these dynamics could inform beekeeping practices, such as designing hives that promote social cohesion or applying synthetic pheromones during heat spikes to safeguard colony health.
Source: https://scientias.nl/honingbijen-zijn-beter-bestand-tegen-hittestress-als-ze-samen-zijn/
