Which bumble bees (Bombus spp.) are in Eau Claire, WI and what do they eat?

Bumble bees (Bombus spp.) are among the most important wild pollinators, contributing significantly to ecosystem health and stability. However, due to habitat loss, climate change, and the continuous increase of pesticide use, many species have experienced population declines. Eau Claire, WI, has been reported as home to 15 Bombus spp. including the endangered Rusty Patched Bumble bee (Bombus affinis), making it an important location for bumble bee conservation. This study aims to characterize foraging behavior and preferences of local Bombus species to improve our understanding of preferred food plants to support conservation. To do this, a 10-week field study will monitor bumblebee abundance and flower preference at three locations around Eau Claire. By conducting 30-minute timed field surveys at each location each week and noting flowers visited, we will evaluate species presence and abundance and create a flower-Bombus interaction network. We expect to observe the Common Eastern Bumble Bee (Bombus impatiens) frequently, as it is the most abundant species in Eau Claire. Additionally, we anticipate encountering some B. affinis given recent sightings of the species. Floral preferences are expected to shift over the season; early in the summer, bumble bees may prefer clover, bee balm, and milkweed, while in the late summer and early fall, goldenrod (Solidago spp.) is likely to become a dominant floral resource, a reported favorite of B. affinis. If we know what the bumble bees like to eat, we can use this data to inform pollinator planting practices in Western WI.