236 - Phytotelmata-inhabiting Culicoides of Miami-Dade County, Florida

Abstract: Biting midges of the genus Culicoides are known vectors of Oropouche virus (OROV) in Central and South America. OROV has historically been endemic to areas in and surrounding the Amazon rainforest, however recent outbreaks of OROV have resulted in a noticeable expansion of transmission and travel related cases to non-endemic areas. Although Local transmission has not yet been documented in the US, South Florida has supported nearly all of the country’s travel-related cases (103/108) as of February 2025. Culicoides paraensis Goeli (Diptera: Ceratopogonidae) is both an enzootic and epidemic vector of Oropouche which is widespread throughout the Americas. As larvae, C. paraensis inhabit tree holes, a life history trait which likely aids in their ability to transmit the virus in both enzootic and urban environments. As a part of investigations for potential OROV vectors in Florida, substrate and water samples were taken from tree holes at eight avocado groves in Miami-Dade County from July to October 2025. Both dry and wet substrates and water samples were taken and place into emergence chambers in a bioroom on a 14–10 light-dark cycle, 60–80% RH, and 25–27°C. Samples were monitored two to three times per week through December 2025. In total, over 450 Culicoides specimen, primarily Culicoides debilipalpis Lutz or Culicoides arboricola Root and Hoffman emerged from 189 treehole samples, and 161 mosquitoes comprising Aedes aegypti Linneaus, Aedes albopictus Skuse, and Aedes triseriatus Say. Culicoides arboricola emerged only from the wet treehole samples which C. debilipalpis emerged from both wet and dry samples. These results are consistent with previous studies which documented that C. paraensis, a member of subgenus Haematomyidium Goeldi along with C. debilipalpis emerge primarily from dry tree hole substrate. This information will aid C. paraensis surveillance in the state of Florida.