D3018: Keeping bumble bees in the dark: Light exposure alters reproductive success of microcolonies

While bumble bees are key pollinators in both natural and agricultural systems, little is known about how light impacts colony reproductive success. In the wild, bumble bees nest underground or in cavities, while managed colonies are kept in colony boxes – both conditions limit exposure of colonies to light. We therefore hypothesized that light exposure would compromise colony growth in bumble bees. To test this hypothesis, we used Bombus impatiens microcolonies (reproductive workers isolated from the queen) to measure potential effects of light on colony growth. Microcolonies were either kept in clear (high light) or black painted (low light) containers for ~ 12 weeks and measured 1) time to first oviposition, 2) worker survival, and 3) total males produced. Preliminary data suggest that workers reared in low light produced more males. Light exposure may stress workers as microcolonies in high light ejected brood more frequently.