A beneficial arthropod dataset for agricultural landscapes in Western Canada and adjacent mountain ecosystems

One of the largest drivers of global biodiversity trends is land use change and habitat loss. Through several studies of beneficial arthropods, we have compiled a spatially- extensive passive-sampling arthropod dataset for Western Canada focused on landscape diversity. This dataset, collected from 2015-2019, consists of more than 200,000 specimens, five arthropod orders, and 26 families of either pollinators (Hymenoptera, Diptera) or natural enemies of pests (Coleoptera, Araneae, Opiliones). In the research that collectively makes up this dataset, there are 409 sampling sites in two focal areas: the Canadian Rockies (n=70) and the agriculturally intense Canadian prairies (n=339).  Sampled in the montane region focused on Bombus species, while both pollinators and natural enemies were sampled in the prairies. Within the prairie region, there was also a focus on non-crop habitat that occurs within or adjacent to the annual crop fields and rangelands that dominate the region. This data can be used to investigate beneficial insect abundance and richness over a gradient of elevation, land cover, landscape diversity and climate.

Methods
The specimens in the dataset came from either montane or prairie sampling sites. The montane data was collected in the Canadian Rockies along hiking trails and used only blue vane traps (SpringStar LLC, Woodinville, WA, USA) meant for sampling arthropod pollinators. The prairie data was primarily collected in intensely agricultural areas and the surrounding non-crop land cover like native prairie grasslands, tree stands, and wetlands. In this area, there were two types of sampling stations- “ditch” stations along road margins that border agricultural areas, or in-field stations that are inside agricultural or non-crop areas. Prairie sites had either a blue vane trap, a pitfall trap, or both. Pitfall traps are made by burying a 528 ml Solo® cups into the ground up to the rim and filling it halfway with propylene glycol and covering it with 2 cm wire mesh to exclude small vertebrates. Sites with both blue vane traps and pitfall traps also had a trio of colored cup traps (3 x 12 oz. white plastic cups with interiors painted fluorescent blue, fluorescent yellow, or left unpainted), which also primarily target pollinators, on posts to be level with the crop canopy.

Across all this research, the deployment and retrieval of traps, as well as the handling of specimens was uniform. The average trap duration is about two weeks, or 13.3 ± 2.8 d (Mean ± SD) and traps were deployed from mid-May to the end of September.  All traps were filled with propylene glycol to catch and preserve arthropods and once collected, trap catch was emptied into WhirlPak® bags with 95% (for the montane sites) or 70% (for prairie sites) ethyl alcohol (EtOH) for transportation back to the lab. A subset of the montaine bee collection is preserved in EtOH, but all other arthropods were washed, pinned, and labelled. All specimens are identified at minimum to the family level, 99.2% are identified to the genus level, and 92.4% are identified to the species level. Some genera are also assigned a subgenus when applicable.

Specimens in the order Hymenoptera (95.6%), Diptera (0.15%), Opiliones (19.9%), and Araneae (93%) are identified to sex, while the Coleoptera are not. Some (4.5%) Araneae and Opiliones are designated immature (I), rather than male (M) or female (F). The social bees of the Apis (23.9%) and Bombus (80%) genera are identified to caste (male, worker, queen) when possible. Each pinned specimen has a species label with taxonomic information and a location label with trap and site information. Each site has a unique 5-digit “beneficials location” ID number (BLID), and each trap has a unique “beneficials trap” ID number (BTID) that is generated as “BLID-pass-replicate-year”. The species label also has a unique 7-digit specimen ID (BBID).  All specimens are kept in the Invertebrate Section of the Museum of Zoology at the Department of Biology, University of Calgary (DBUC)