Abstract The extent of anthropogenic habitats that support species-rich assemblages of bees and wasps is poorly understood. In the present study, we identified a previously overlooked hotspot of bee and wasp (Hymenoptera: Aculeata) biodiversity that consists of bare loess exposed by anthropogenic activities, mostly in clay pits but also in slopes of sunken lanes or upper berms of sand pits. We examined the diversity of bees and wasps in microhabitats with exposed bare loess at 17 sampling sites, which were located throughout the Czech Republic. Using color pan traps and metal-roof-bearing pitfall traps, we identified 328 species of bees and wasps, of which 61 were threatened. The threatened species were dominated by specialists for loessic, sandy and steppic habitats but included also several wetland specialists. The examined assemblages were rich in threatened polylectic pollinators and threatened predators of Lepidoptera, Araneae, Diptera and Auchenorrhyncha. The present oligolectic pollinators were mostly specialists for Asteraceae, Fabaceae and Rosaceae. Importantly, the spectrum of species found overlapped only partly with those identified previously in other anthropogenic habitats, and 83 species, of which 35 were considered threatened, were absent from the compared studies at all. The two capture methods used generated different results; color pan traps were dominated by polylectic pollinators, whereas the pitfall traps attracted multiple predatory species. The analyzed assemblages of aculeate hymenopterans were characterized by their low dominance (1-Simpson index 0.066) and high alpha diversity (Fisher's alpha 66.4). We concluded that bare loess exposed by anthropogenic activities allows the formation of species-rich assemblages of aculeate hymenopterans, which include numerous species that become rare in cultural landscapes.

中文翻译：

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识别以前被忽视的人类栖息地，该栖息地吸引了各种受威胁的蜜蜂和黄蜂

摘要 支持蜜蜂和黄蜂物种丰富的组合的人为栖息地的范围知之甚少。在本研究中，我们确定了一个以前被忽视的蜜蜂和黄蜂（膜翅目：Aculeata）生物多样性热点，它由人类活动暴露的裸露黄土组成，主要位于粘土坑中，但也位于下沉车道的斜坡或沙坑的上部护堤中。我们在位于捷克共和国各地的 17 个采样点检测了裸露黄土微生境中蜜蜂和黄蜂的多样性。使用彩盘陷阱和金属屋顶陷阱陷阱，我们确定了 328 种蜜蜂和黄蜂，其中 61 种受到威胁。受威胁的物种主要由黄土、沙地和草原栖息地的专家主导，但也包括一些湿地专家。检查的组合富含受到威胁的多聚传粉昆虫和鳞翅目、蜘蛛目、双翅目和 Auchenorrhyncha 的受威胁捕食者。目前的寡聚传粉者主要是菊科、豆科和蔷薇科的专家。重要的是，发现的物种范围与之前在其他人为栖息地中发现的物种仅部分重叠，比较研究中根本没有发现 83 种物种，其中 35 种被认为受到威胁。使用的两种捕获方法产生了不同的结果；彩色盘捕集器由多种传粉者主导，而陷阱捕集器吸引了多种掠食性物种。分析的有刺膜翅目昆虫组合的特征在于它们的低优势（1-辛普森指数 0.066）和高 alpha 多样性（Fisher's alpha 66.4）。