EVALUATING SOLITARY BEE NESTING PREFERENCE – DOES THE GROUND COVER MATTER?

Abstract

Solitary bees make up the majority of the world’s 20,000 total species of bees. Over 70% of solitary bees nest underground. Bee fitness is likely determined, in part, by the proximity to appropriate nesting sites. Identifying ground cover management that optimally supports bee nesting could help inform and improve conservation efforts. To date, little is known about the impact ground cover has on ground nesting bees nesting success. To start to fill this gap in knowledge, this study monitored 4 plots, located in Maryland, with different ground cover treatments from early May to mid-July in 2020. Emergence traps were utilized to capture nesting solitary bees within the 4 treatments – solarized bare ground, wildflowers, un-mown grass, and mown grass. When compared to cut grass and uncut grass, we found that emergence traps were 5 to 7 times more likely to catch solitary bees when placed over bare soil plots. This suggests that more bees nest in ground that starts bare or contains significant bare patches. Although the covid pandemic limited the number of sites monitored and reduced the time frame of the study, the preliminary research results provide guidance to homeowners and land managers that wish to manage landscapes in ways that support solitary bee nesting.