Abstract The temperature of the nest influences fitness in cavity-nesting bees. Females may choose nest cavities that mitigate their offspring's exposure to stressful temperatures.This study aims to understand how cavity temperature impacts the nesting preference of the solitary bee Megachile rotundata (Fabricius) under field conditions. We designed and 3D printed nest boxes that measured the temperatures of 432 cavities. Nest boxes were four-sided with cavity entrances facing northeast, northwest, southeast, and southwest. Nest boxes were placed along an alfalfa field in Fargo, ND and were observed daily for completed nests. Our study found that cavity temperature varied by direction the cavity faced and by the position of the cavity within the nest box. The southwest sides recorded the highest maximum temperatures while the northeast sides recorded the lowest maximum temperatures. Nesting females filled cavities on the north-facing sides faster than cavities on the south-facing sides. The bees preferred to nest in cavities with lower average temperatures during foraging hours, and cavities that faced to the north.The direction the cavity faced was associated with the number of offspring per nest.The southwest-facing cavities had fewer offspring than nests on the northeast side. Our study indicates that the nesting box acts as a microclimate, with temperature varying by position and direction of the cavity. Variation in cavity temperature affected where females chose to nest, but not their reproductive investment.

中文翻译：

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小气候温度影响 Megachile rotundata（膜翅目：Megachilidae）的筑巢偏好

摘要 巢穴温度影响穴居蜂的适应度。雌性可能会选择可以减轻后代暴露于压力温度的巢穴。本研究旨在了解巢穴温度如何影响野外条件下独居蜜蜂 Megachile rotundata (Fabricius) 的筑巢偏好。我们设计并 3D 打印了巢箱，可测量 432 个腔的温度。巢箱为四边形，洞口面向东北、西北、东南和西南。巢箱沿着北卡罗来纳州法戈的苜蓿田放置，每天观察完成的巢。我们的研究发现，腔温度因腔面向的方向和巢箱内腔的位置而异。西南侧的最高气温最高，而东北侧的最高气温最低。筑巢的雌性填充朝北侧的空腔比填充朝南侧的空腔快。蜜蜂喜欢在觅食期间平均温度较低的洞穴和朝北的洞穴中筑巢。洞穴面向的方向与每个巢的后代数量有关。西南洞穴的后代数量少于南方的巢穴。东北侧。我们的研究表明，筑巢箱就像一个小气候，温度随腔的位置和方向而变化。腔内温度的变化会影响雌性选择筑巢的位置，但不会影响它们的生殖投资。筑巢的雌性填充朝北侧的空腔比填充朝南侧的空腔快。蜜蜂喜欢在觅食期间平均温度较低的洞穴和朝北的洞穴中筑巢。洞穴面向的方向与每个巢的后代数量有关。西南洞穴的后代数量少于巢穴上的巢。东北侧。我们的研究表明，筑巢箱就像一个小气候，温度随腔的位置和方向而变化。腔内温度的变化会影响雌性选择筑巢的位置，但不会影响它们的生殖投资。筑巢的雌性填充朝北侧的空腔比填充朝南侧的空腔快。蜜蜂喜欢在觅食期间平均温度较低的洞穴和朝北的洞穴中筑巢。洞穴面向的方向与每个巢的后代数量有关。西南洞穴的后代数量少于巢穴上的巢。东北侧。我们的研究表明，筑巢箱就像一个小气候，温度随腔的位置和方向而变化。腔内温度的变化会影响雌性选择筑巢的位置，但不会影响它们的生殖投资。洞面向的方向与每个巢的后代数量相关。面向西南的洞的后代比东北侧的巢少。我们的研究表明，筑巢箱就像一个小气候，温度随腔的位置和方向而变化。腔内温度的变化会影响雌性选择筑巢的位置，但不会影响它们的生殖投资。洞面向的方向与每个巢的后代数量相关。面向西南的洞的后代比东北侧的巢少。我们的研究表明，筑巢箱就像一个小气候，温度随腔的位置和方向而变化。腔内温度的变化会影响雌性选择筑巢的位置，但不会影响它们的生殖投资。