Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Parma Research Station, ID 83660, USA.
Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA.
J Insect Sci. 2022 Jul 1;22(4). doi: 10.1093/jisesa/ieac042.
The alfalfa leafcutting bee Megachile rotundata Fabricius (HYMENOPTERA: Megachilidae) is an important pollinator for multiple agricultural seed commodities in the United States. M. rotundata is a solitary cavity nesting bee that forms brood nests where its larvae can develop. During the developmental stages of growth, brood can be preyed upon by multiple different fungal pathogens and insect predators and parasitoids, resulting in the loss of the developing larvae. Larval loss is a major concern for alfalfa (Medicago sativa L.) seed producers because they rely on pollination services provided by M. rotundata. Reduced pollination rates result in lower yields and increased production costs. In the present study, we examined the taxonomic composition of organisms found within M. rotundata brood cells using a multiplex PCR assay which was developed for the detection of bacterial, fungal, and invertebrate pests and pathogens of M. rotundata larvae. Known pests of M. rotundata were detected, including members of the fungal genus Ascosphaera, the causative agent of chalkbrood. The presence of multiple Ascosphaera species in a single brood cell was observed, with potential implications for chalkbrood disease management. The multiplex assay also identified DNA from more than 2,400 total species, including multiple predators and pathogenetic species not previously documented in association with M. rotundata brood cells.
苜蓿叶象甲 Megachile rotundata Fabricius（膜翅目：叶蜂科）是美国多种农业种子商品的重要传粉媒介。M. rotundata 是一种独居的腔巢筑巢蜂，其幼虫可以在那里发育。在生长的发育阶段，幼虫可能会受到多种不同的真菌病原体和昆虫捕食者和寄生蜂的捕食，导致幼虫死亡。幼虫损失是紫花苜蓿（Medicago sativa L.）种子生产者的主要关注点，因为它们依赖 M. rotundata 提供的传粉服务。授粉率降低会导致产量降低和生产成本增加。在本研究中，我们使用针对 M. rotundata 幼虫的细菌、真菌和无脊椎动物害虫和病原体检测的多重 PCR 检测方法，检查了在 M. rotundata 幼虫巢细胞中发现的生物的分类组成。检测到了 M. rotundata 的已知害虫，包括 chalkbrood 的病原体 Ascosphaera 属的真菌成员。在单个巢细胞中观察到多种 Ascosphaera 物种的存在，这可能对 chalkbrood 疾病管理有影响。多重分析还鉴定了来自超过 2400 个总物种的 DNA，包括以前未记录与 M. rotundata 幼虫巢细胞有关的多种捕食者和病原物种。
