Culicoides (Diptera: Ceratopogonidae) communities differ between a game preserve and nearby natural areas in northern Florida

Authors: McGregor, Bethany; BLACKBURN, JASON - University Of Florida; WISELY, SAMANTHA - University Of Florida; BURKETT-CADENA, NATHAN - University Of Florida

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2021
Publication Date: 1/13/2021
Citation: McGregor, B.L., Blackburn, J.K., Wisely, S.M., Burkett-Cadena, N.D. 2021. Culicoides (Diptera: Ceratopogonidae) communities differ between a game preserve and nearby natural areas in northern Florida. Journal of Medical Entomology. 58(1):450-457. https://doi.org/10.1093/jme/tjaa152.
DOI: https://doi.org/10.1093/jme/tjaa152

Interpretive Summary: Culicoides biting midges are small flies that are known to blood feed on a variety of vertebrate animals worldwide. While blood feeding, they can also transmit numerous diseases of livestock including bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). Due to their impact on economically valuable livestock industries, it is important that we evaluate factors affecting the abundance of midges and their ability to spread diseases. White-tailed deer, a species which is farmed in the United States, can occur at high densities on farms, providing an ample source of blood for female midges. This study evaluated whether a big game preserve with a high animal density in the Florida panhandle had greater midge abundance than nearby public lands where host animal populations were naturally lower. Greater midge abundance was collected on the preserve and at a site next to the preserve than at more distant sites outside of the typical dispersal range of midges. Importantly, this trend was observed for species suspected as vectors of BTV and EHDV. This research shows that high animal densities on farms may lead to a greater abundance of midges and ultimately greater potential for the spread of midge-borne diseases than more natural sites with lower animal densities. These data can be used to recommend that deer farmers maintain lower animal densities on farms as a preventative measure against high midge abundance and associated disease transmission.

Technical Abstract: Culicoides Latrielle biting midges are small hematophagous flies known to feed on a variety of vertebrate animals worldwide. White-tailed deer (Odocoileus virginianus), a species which is farmed in the United States, can occur at high densities on farms, providing an ample source of blood for female midges. This elevated density of available hosts may result in greater abundance of midges and greater potential for disease transmission on deer farms than in natural ecosystems. The present research aimed to determine whether Culicoides abundance varied significantly between a big game preserve in Gadsden County, Florida, a site bordering the preserve (“adjacent”), a site 3.5km from the preserve (“moderate”), and a site 13km from the preserve (“distant”). CDC miniature light traps with LED black light arrays were set one night per week at the preserve, the adjacent site, and the moderate site in 2016 (11 total weeks) and at all four sites in 2017 (12 total weeks). Total abundance of Culicoides was greatest at the preserve and second greatest at the adjacent site during both years. Average abundance of female C. stellifer was an order of magnitude greater on the preserve (x¯=24.59 in 2016, 17.95 in 2017) than at any other site(x¯ =1.68 in 2016, x¯ =1.03 in 2017), while the greatest average abundance of C. venustus was found at the adjacent site (x¯=5.15 in 2016, x¯=1.92 in 2017). Distance from the preserve was found to significantly affect overall average abundance for both species (P<0.001), although pairwise significance between sites varied. Species diversity was found to be lowest on the preserve site and highest at the moderate site both years. These data suggest that artificially high densities of animals may increase transmission potential on high fence preserves and in areas adjacent to them by contributing to artificially high densities of vector species.