Survey of Hymenoptera Pollinator Populations on Washington Island, Wisconsin

Kate Markiewicz

Conservation and Environmental Science Program, UW-Milwaukee, markie23@uwm.edu

Pollinating insects are highly beneficial in both natural ecosystems and agriculture, but many species are in decline. This project’s goal was to survey Hymenoptera pollinators on Washington Island, WI, and to explore factors influencing their abundance and diversity. The two sites included the Washington Island Butterfly House, which has undergone extensive prairie restoration, and Sweet Mountain Farm, an apiary breeding western honey bees. Surveys took place 1-3 times per week, during which records on flowering species, weather conditions, and pollinators were obtained. Each day, three patches of flowering plants were chosen to include the most prevalent species within a one m2 quadrat and observed for ten minutes after a one minute “resting period”. All insects that contacted a flower were tallied as pollinators. At both sites, varying numbers of honey bees, bumblebees, sweat bees, and wasps were found visiting flowers. Results showed that along with a higher plant diversity, the Butterfly House had greater variety and abundance of Hymenoptera, with 53% sweat bees, 19% honey bees, and 19% wasps. Sweet Mountain Farm, showing less plant diversity and a strong presence of invasive plants, had less variety of Hymenoptera. The site was dominated by honey bees raised on the property, which comprised nearly 75% of all pollinators recorded. At both sites, bumblebees were the least abundant species at 3-4%. In the future, the Butterfly House’s prairie restoration efforts can serve as an example for other sites, like Sweet Mountain Farm, to increase both native and introduced pollinators. Undergraduate research project, Dr. Gretchen Meyer, advisor.