Edge effects and pitfall trap design influence spider diversity and assemblages in canola agroecosystems on the Canadian Prairies
Data files
Sep 23, 2025 version files 167.60 KB
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README.md
4.94 KB
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Spiders_2021-2022.xlsx
42.69 KB
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Spiders_2023.xlsx
119.97 KB
Abstract
Spiders (Araneae) are generalist predators in agroecosystems and may contribute to biological control in canola (Brassica napus L. and B. rapa L.). However, their diversity and community structure remain understudied in the Canadian Prairies. To address this knowledge gap, we surveyed spider assemblages in the Aspen Parkland region of Alberta, Canada, using pitfall traps placed at field edges and interiors during the 2021 and 2022 growing seasons. In 2023, we tested pitfall trap modifications to improve spider retention, evaluating: 1) trap diameter, 2) preservative substrate (glass beads vs. propylene glycol), and 3) polytetrafluoroethylene (PTFE; Fluon, a non-stick fluoropolymer) coated trap interiors (to reduce friction and prevent escape). This was tested across canola habitats adjacent to grass- or tree-dominated non-crop habitat edges. The uploaded dataset contains all spider identifications from 2021 to 2023.
Dataset DOI: 10.5061/dryad.34tmpg4xh
Description of the data and file structure
Spider diversity and composition in canola. To assess spider diversity and activity density in canola fields, pitfall trapping was conducted between June and August 2021 (n = 5 sites) and 2022 (n = 5 sites). At each site, two parallel 100 m transects were established: one at a field edge, adjacent to semi-natural non-crop habitat (0.5 m from the edge), and another one at the field interior (100 m into the field).
Pitfall trap design comparisons. To optimize the pitfall trap design to improve spider retention, an experiment was conducted in 2023. The experiment evaluated the impact of pitfall trap diameter (small, medium, large), preservation method (i.e., killing agent (propylene glycol) vs. live trapping (glass beads)), interior trap wall non-stick coating (polytetrafluoroethylene , PTFE), and collection period length (7 days and 24-hours) on spider sampling.
Files and variables
Spiders_2021-2022.xlsx - Spider diversity and composition in canola. All identification data of spiders collected in canola fields in 2021 and 2022.
| Column Header | Definition |
|---|---|
| Sample ID | Sample identifier (combination of fieldID, transect, and collection date) |
| TrapID | Trap identifier (combination of fieldID, transect, and trap number) |
| Year | Year of collection |
| FieldID | Field identifier |
| Transect | Edge (E) or Interior (I) transect |
| ColDat | Collection date |
| Family | Family |
| Genus | Genus |
| Specific epithet | Specific epithet |
| Sex | Male (M), Female (F) or underdetermined (NA) |
| Count | Number of spiders collected |
| Species full | Species name |
Spiders_2023.xlsx - Pitfall trap design comparisons. All identification data of spiders collected near canola fields in 2023.
| Column Header | Definition |
|---|---|
| Sample ID | Sample identifier (combination of fieldID, transect, and collection date) |
| TrapID | Trap identifier (combination of fieldID, transect, and trap number) |
| Year | Year of collection |
| Timeframe | 7 day sampling period (7D) or 24 hours (24H) |
| FieldID | Field identifier |
| Habitat | Habitat which the traps were setup. Grass (GR) or tree (TR) |
| Size | Trap diameter: small (S), medium (M) or large (L) |
| Treatment | Trap treament. One of: |
| Trap with Propylene Glycol and No Fluon (PG0) | |
| Trap with Propylene Glycol and Fluon (PGF) | |
| Dry trap without Fluon (D0) | |
| Dry trap with Fluon (DF) | |
| ColDat | Collection date |
| Family | Family |
| Genus | Genus |
| Specific epithet | Specific epithet |
| Sex | Male (M), Female (F) or underdetermined (NA) |
| Count | Number of spiders collected |
| Species full | Species name |
Code/software
Microsoft Excel, Google Sheets, or an editor capable of viewing .xlsx files.