Saccharine Ceratopogonids: Sugar feeding ecology and behaviors of Culicoides biting midges (Diptera: Ceratopogonidae).

Abstract

Culicoides is a diverse genus of approximately 1,300 species of small biting flies found across the globe (Borkent and Dominiak 2020), containing numerous species that can transmit viral pathogens which cause mortality in livestock and wildlife and can infect people. These diseases have no direct treatment, so prevention through vector control is paramount. Current surveillance and control methods are limited by a lack of ecological knowledge of Culicoides, particularly phytophagous (sugar feeding) behavior. The plants fed on by Culicoides are largely unknown, as are the driving forces behind choosing these plants. This information could be vital for improving control strategies through increased trap attraction and/or application in other management methods. To determine what plants are being fed on, Culicoides were collected from northeastern Kansas and sugar meal analysis performed on plant DNA extracted from midge bodies. Biting midges were found to feed on a diverse group of plant families, including Amaranthaceae, Solanaceae, and Cupressaceae, indicating multiple sugar sources including nectar and fruit are utilized under natural conditions. Using two-choice behavioral bioassays, the role of sight and color preference in sugar feeding choice behavior was analyzed in laboratory colony midges. When presented with differently colored simulated flowers in the lab, Culicoides exhibit a preference for red over purple. However, a strong preference also existed for the flower on the right side of the assay chamber, indicating other cues such as inflorescence type or olfactory stimuli may also be important and should be further investigated.