Development and lifespan of Culicoides obsoletus s.s. (Meigen) and other livestock-associated species reared at different temperatures under laboratory conditions.

Abstract

Culicoides Latreille (Diptera: Ceratopogonidae) transmit arboviruses affecting wild and domestic ruminants such as bluetongue (BTV) and Schmallenberg virus (SBV). The sub-adult development and lifespan of Culicoides obsoletus s.s. (Meigen), Culicoides circumscriptus Kieffer and Culicoides paolae Boorman were examined at three different temperatures under laboratory conditions. Insects were collected from field between spring and autumn 2015 in two livestock farms located in Majorca (Spain). Gravid females were held individually at 18, 25 or 30 °C. Low temperatures increased the adult lifespan, time to oviposit and rate of development, whereas high temperatures increased the number of eggs, successful pupation and adult emergence as well as the larvae growth rate. The results showed that C. obsoletus s.s. have optimum development at 18 °C, whereas the optimal rearing temperature for C. circumscriptus and C. paolae was under warmer conditions of 25-30 °C. Variations in temperature/humidity and assays with different materials and substrates for oviposition should be considered in future studies. Understanding the requirements of the different species of Culicoides optimizing the results should be of special interest for predicting environmental change effects on these species, in addition to determining the rearing conditions for candidate Culicoides vectors.