Predicting the effects of climatic warming on social insects remains an important challenge. While warming is known to speed many rate processes, the acute effects of temperature on performance under field conditions remain poorly studied. The effects of temperature are usually nonlinear, and tropical animals have been predicted to be particularly likely to be negatively affected by global warming as they may have optimal temperatures that are close to current ambient temperatures. We observed three different A. colombica colonies three times per day (two times during daylight hours and one time at night) during June 2018 in Gamboa, Panama, measuring air temperature, ant traffic, intake of leaves per second, and ant walking speeds. We found that ant walking speed and intake of leaves increased at higher temperatures. Leaves carried per ant also increased with temperature, suggesting that warmer temperatures improve leaf-handling rates, at least over the thermal range studied here. However, there was also an independent effect of time of day, with higher foraging in the morning than the evening, despite similar air temperatures. Consistent with the positive effect of temperature on foraging rates, critical thermal maxima were well above ground temperatures. At least during the rainy season, our data suggest that moderate warming could enhance foraging success and herbivory of leafcutting ants in semi-deciduous moist forests throughout much of the day.

中文翻译：

---

在雨季期间，温暖的中午温度通过提高 Atta colombica 的觅食速度和成功率来增加叶子的摄入量

预测气候变暖对社会昆虫的影响仍然是一个重要的挑战。虽然已知变暖会加速许多速率过程，但温度对田间条件下性能的急性影响仍然缺乏研究。温度的影响通常是非线性的，据预测热带动物特别有可能受到全球变暖的负面影响，因为它们的最佳温度可能接近当前环境温度。我们于 2018 年 6 月在巴拿马甘博亚每天观察了三个不同的 A. colombica 群体 3 次（白天两次，夜间一次），测量气温、蚂蚁流量、每秒叶子摄入量和蚂蚁行走速度。我们发现蚂蚁的行走速度和叶子的摄入量在较高的温度下增加。每只蚂蚁携带的叶子也随着温度的升高而增加，这表明较高的温度会提高叶子处理率，至少在此处研究的温度范围内是这样。然而，一天中的时间也有独立的影响，尽管气温相似，但早晨的觅食量比晚上高。与温度对觅食率的积极影响一致，临界热最大值远高于地温。至少在雨季，我们的数据表明，在一天的大部分时间里，适度变暖可以提高半落叶潮湿森林中切叶蚁的觅食成功率和食草性。尽管气温相似，但早晨的觅食量比晚上高。与温度对觅食率的积极影响一致，临界热最大值远高于地温。至少在雨季，我们的数据表明，在一天的大部分时间里，适度变暖可以提高半落叶潮湿森林中切叶蚁的觅食成功率和食草性。尽管气温相似，但早晨的觅食量比晚上高。与温度对觅食率的积极影响一致，临界热最大值远高于地温。至少在雨季，我们的数据表明，在一天的大部分时间里，适度变暖可以提高半落叶潮湿森林中切叶蚁的觅食成功率和食草性。