In hot climates, foraging bees risk overheating during food collection. Here, we investigated influence of ambient temperature on the foraging activity in Melipona subnitida, a stingless bee species that naturally occurs in the hottest and driest regions of the Brazilian tropical dry forest. We observed a decrease in round-trip duration of pollen foragers with increasing ambient temperature. Foraging duration of nectar collectors, however, was not affected by the thermal conditions of the environment. When exposed to heat stress in incubators, the upper thermal limits of foragers decreased with increasing exposure time. Moreover, individuals with previous access to liquid food showed higher critical and lethal temperatures than unfed bees. Our study revealed plastic changes in the upper thermal limit of M. subnitida, which help to understand the foraging activity pattern of this stingless bee species.

中文翻译：

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不要在外面呆太久！无刺蜜蜂 Melipona subnitida 的耐热性随着暴露在高温下的时间增加而降低

在炎热的气候下，觅食的蜜蜂在收集食物时可能会过热。在这里，我们调查了环境温度对 Melipona subnitida 觅食活动的影响，Melipona subnitida 是一种天然存在于巴西热带干旱森林最热和最干燥地区的无刺蜜蜂物种。我们观察到随着环境温度的升高，花粉觅食者的往返持续时间减少。然而，花蜜采集者的觅食持续时间不受环境热条件的影响。当在孵化器中暴露于热应激时，觅食者的热上限随着暴露时间的增加而降低。此外，与未喂食的蜜蜂相比，以前接触过液体食物的个体表现出更高的临界温度和致死温度。我们的研究揭示了 M. subnitida 热极限的塑性变化，