Petals and leaves: quantifying the use of nest building materials by the world’s most valuable solitary bee

The alfalfa leafcutter bee (“ALCB”, Megachile rotundata) is a solitary, cavity-nesting bee native to Eurasia, managed as an agricultural pollinator of alfalfa and several other crops in North America since the 1940s (Pitts-Singer and Cane 2011). The most intensively managed and economically valuable solitary bee worldwide, it serves as a model organism for studying solitary bee biology (Pitts-Singer and Cane 2011). Understanding this species’ nesting behavior is critical to its propagation for commercial pollination services. As its common name suggests, female ALCBs construct their nests in above-ground holes using carefully clipped pieces of leaves (Pitts-Singer and Cane 2011).苜蓿切叶蜂（alfalfa leafcutter bee，简称ALCB，学名Megachile rotundata）是一种独居、洞穴筑巢的蜂类，原生分布于欧亚大陆，自20世纪40年代起便被作为苜蓿及其他多种作物的农业授粉蜂在北美开展规模化管理（Pitts-Singer与Cane，2011）。该蜂是全球集约化管理程度最高、经济价值最大的独居蜂类，同时也是研究独居蜂生物学的模式生物（Pitts-Singer与Cane，2011）。明晰该物种的筑巢行为，对其商业化授粉服务的繁育工作至关重要。正如其通用名称所示，雌性ALCB会利用精心裁剪下的叶片在地上孔洞中构筑巢穴（Pitts-Singer与Cane，2011）。