1. Recent evidence indicates that many native bee species are in decline due to the cumulative effects of multiple human-induced stressors such as habitat loss, pesticide exposure, pathogens, and climate change. These declines have raised interest in the status of native bees and in developing tools that support management of bee communities and the ecosystem services they deliver. 2. Native bees were surveyed using pan traps and netting over 2 years at 68 locations in croplands and rangelands across three ecological regions of Alberta's prairiesthe Grassland, Parkland, and Boreal Natural Regionsto evaluate patterns in bee communities in response to disturbance and ecological gradients. 3. Bee community composition was different across land use and ecoregions. While several cavity-nesting species had a strong association with rangelands, cavity-nesting bees tended to be less common in croplands and may be more sensitive to loss of rangeland habitat. 4. Response patterns in overall bee abundance and richness were driven by interactions between region and land use, highlighting the need for regional studies to understand how bee communities respond to these factors. 5. This survey is one of the first to sample the response of bee communities to landscape disturbance across a broad spatial area of the Canadian prairies. Large-scale compositional studies are essential for understanding the status of native bee communities, and for monitoring long-term trends over time. We recommend subsequent coordinated surveys using standardised methods across broad spatial scales.

Semiochemical-baited traps are commonly used to monitor moth pests and inform management decisions. Unfortunately, bee pollinators can be unintentionally captured, which reduces monitoring system efficiency and may negatively impact pollinator biodiversity and pollination services. We assessed the abundance and diversity of wild bees captured in semiochemical-baited traps designed to capture cutworm and armyworm (Lepidoptera: Noctuidae) pests in North America. Green Unitraps were baited with semiochemicals including: (1) species-specific noctuid pheromone lures; (2) food bait lures consisting of fermentation by-products; or (3) floral volatiles. Traps were positioned in canola (Brassica napus L.) and wheat (Triticum aestivum L.) fields in Alberta, Canada. We also explored the mechanisms of bee detection of moth pheromone components using electroantennogram (EAG) assays to assess the antennal response of two Bombus species. We found that more bumble bees (Hymenoptera: Apidae), and especially Bombus rufocinctus Cresson, were captured in traps baited with moth pheromone lures than in unbaited control traps. Fermentation by-product lures captured a similar low number of bees as unbaited traps, whereas floral volatile-based food bait lures captured more bees, comparable to capture in pheromone-baited traps. In general, more Bombus spp. were captured in traps positioned at canola vs. wheat fields, but the community composition was similar among crops. EAG assays indicate that sensory receptors on the antennae of B. rufocinctus Cresson and B. impatiens Cresson detect noctuid moth pheromones. Perception of chemical signals of a different insect order may be explained by structural similarities in pheromone components produced by both moths and bumble bees.

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