Using collection bottle rotator traps and stable isotopes to elucidate Culicoides movement across an ecotone habitat

Understanding how insect vectors are distributed across a landscape is necessary for monitoring pathogen transmission and implementing vector control tools. However, fine-scale studies of this distribution are often lacking. Culicoides biting midges develop in diverse aquatic and semi-aquatic habitats. Although they can travel up to 100km if aided by wind, Culicoides tend to actively disperse only short distances (< 5km), and remain near their development site.
Culicoides movement between habitat types is not well understood. Our previous work suggested that some Culicoides species move between forest and pastures to feed on cattle. To determine patterns of Culicoides dispersal, we are using timed, collection bottle rotator traps set on a 100m transect between a forest and a cattle pasture. Traps were set from May to October 2025 and programmed to collect at 2h intervals (1600-0800). In addition to the bottle rotator traps, mock Culicoides developmental sites were set at 7m and 22m from the tree line in February 2024. These buckets were enriched with stable isotopes (13C at 7m and 15N at 22m) approximately every 3 months. Collected midges will be processed for stable isotope analysis at the University of Arkansas Stable Isotope Laboratory to determine whether midges which develop in forest habitats will actively enter pastures to host-seek. The timed collections and stable isotope labeling will allow us to examine fine-scale movement patterns of host-seeking Culicoides. The results of this study will inform producers on how far Culicoides are willing to disperse to improve control techniques.