Do passive samplers track pesticide application patterns and represent exposure to foraging bumble bees?

Authors: Schneider, Sharon; Roeder, Karl; HLADIK, MICHELLE - Us Geological Survey (USGS); Sutradhar, Apurba

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/21/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Significant research has been published regarding exposure of honey bees to pesticides, but limited information is available for other managed and wild bee species. Bees have differential foraging and food consumption behaviors that can vary during the season and may affect their exposure to pesticides. In preliminary research, we found that Melissodes spp. (long-horned bees) collected from three sites in South Dakota carried insecticides, fungicides, and herbicides throughout their foraging time, from July through November, with the frequency and concentration of chemicals generally highest in July and August. In a larger study, we sought to (a) evaluate the temporal distribution of pesticide concentrations in native bees; (b) compare pesticide detections against expected field use patterns (e.g., rate and timing of pesticide application); (c) evaluate whether pesticides carried by field-deployed colonies of common eastern bumble bees (Bombus impatiens) correlate with pesticides carried by wild bees collected during the same time; (d) assess pesticide partitioning to hive structures and brood in B. impatiens colonies; and (e) evaluate whether passive silicone samplers can serve as a reasonable proxy for free foraging bees with respect to pesticide concentrations. We focus here on results for B. impatiens colonies and passive samplers. From May through September, 10 queenright colonies were deployed for one month at an agricultural site in South Dakota. A passive silicone band sampler was installed at the site of each colony. Every two weeks, 10 workers were removed from each colony and frozen for future analysis. Colonies and passive samplers were retrieved at 4 weeks post-deployment and replaced with a new queenright colony. Samples were extracted using pressurized solvent extraction, cleaned, and analyzed by both gas and liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS). Concentrations of >150 insecticides, fungicides, and herbicides were measured, including compounds known or expected to be used in the region. Results may indicate the potential for bumble bee colonies or passive samplers to represent pesticide exposure to wild bees, and implications for pesticide transfer to subsequent generations.