Is roadside disturbance 'no sweat' for sweat bees?

IS ROADSIDE DISTURBANCE 'NO SWEAT' FOR SWEAT BEES?

Melissa Broussard, Sujaya Rao, and William P. Stephen

Oregon State University, Department of Crop and Soil Science, 3017 ALS, Corvallis, OR

Native bees respond to habitat changes and hence they have become increasingly important as bioindicators for habitat disturbance. Previous studies have focused on habitat fragmentation, while other pervasive types of disturbance have received limited attention. The objective of this study was to determine if native bee species could serve as indicators for roadside disturbance. As sweat bees (Apoidea: Halictidae) are often found in areas of high disturbance, this family was the focal group for our study. In 2011, we sampled Oregon's eight ecoregions three times from spring to late summer. At each site, bees were hand-collected from a roadside and a paired 'natural' area. Close to 1,000 halictids were collected, including five genera and >20 species. Data analysis using paired t-tests and ANOVA indicated that, despite their reputation for thriving in disturbed areas, the large subgenus Lasioglossum (Dialictus) showed a negative response to roadside disturbance after accounting for other variables (P=0.05). These results, and others related to spatial distribution and forage plants of halictids in Oregon will be presented. Implications of the findings for further ecological studies and sweat bee conservation programs will also be discussed.