ERISTALIS TENAX MOVEMENT BEHAVIOR IN RESPONSE TO LIGHT, TEMPERATURE, AND FOOD.

Drone flies, Eristalis tenax (Diptera: Syrphidae), are important generalist pollinators and visit flowers globally that range widely in color. The flies' photoreceptors allow them to sense light wavelengths between 300-600 nm and E. tenax exhibit a positive phototactic response. To understand the effects of light on E. tenax movement, we conducted two- choice behavioral tests to determine their phototactic response to different wavelengths of light across the spectrum (ultraviolet to red light, plus full spectrum white light). The drone flies moved most and quickest toward sunlight, with almost twice the percentage of flies moving toward sunlight than toward black and purple light (short wavelength sources), which elicited the second strongest phototactic responses. Eristalis tenax moved minimally toward green and red light sources. When increasing air temperature by 6°C, the percent of E. tenax moving toward fluorescent white light increased by a factor of four. They also moved toward a food source in light but not dark conditions. Our findings may be useful for managing E. tenax populations in the lab or for increasing crop pollination. [ABSTRACT FROM AUTHOR]