Seasonal and Nocturnal Activity of Culicoides spp. (Diptera: Ceratopogonidae) Adapted to Different Environments in the Balearic Islands

Several pathogens are known to be transmitted by arthropods. One of the most relevant, in economic terms, affecting animals is bluetongue virus. Its known vectors are several species of Culicoides midges. In Europe, the considered main vector species are Culicoides imicola and Culicoides obsoletus, though other species may be implicated at different levels. In the present work, the activity of these vector species between sunset and sunrise from May to November is analyzed according to their captures in a rotator bottle collector adapted to a light trap. Additionally, the Culicoides populations of two areas in Mallorca (Spain) with different characteristics (rural vs. urban) are compared. The results indicated that June is the month of higher abundance of C. obsoletus in our climatic conditions-being active during the first three hours after sunset. Conversely, C. imicola reached the maximum level of captures during October, and captures were more evenly distributed during the night. Collections from the two areas revealed that Culicoides populations were composed by the same species; however, abundance and sex ratio presented marked differences. These results add valuable insight into the ecology of Culicoides and may be used to design more accurate strategies to control diseases associated with Culicoides.

Automated summary

This study analyzed the activity of two vector species, Culicoides imicola and Culicoides obsoletus, in Europe during the period from sunset to sunrise. It also compared the Culicoides populations in two different areas in Mallorca, Spain. The results showed that C. obsoletus was most abundant in June and active during the first three hours after sunset, while C. imicola had the highest captures in October and more evenly distributed activity during the night. The populations in the two areas were composed of the same species, but had significant differences in abundance and sex ratio. These findings provide valuable insights for understanding the ecology of Culicoides and developing more effective strategies for disease control.