Spatial and temporal distribution of Culicoides species in the New England region of New South Wales, Australia between 1990 and 2018

Abstract

Culicoides are one of the smallest hematophagous flies measuring 1–5 mm in size with only females seeking blood for egg development. The present study investigated spatio-temporal distribution of Culicoides species trapped between 1990 and 2018 at 13 sites in the New England region of NSW, Australia using automated light traps. Trapping locations were divided into three subregions (tablelands, slopes and plains). Nineteen Culicoides species were identified. Culicoides marksi and C. austropalpalis were the most abundant and widespread species. Culicoides brevitarsis, the principal vector of livestock diseases in New South Wales comprised 2.9% of the total catch and was detected in 12 of the 13 locations in the study. Abundance as determined by Log10 Culicoides count per trapping event for the eight most abundant species did not vary significantly with season but trended towards higher counts in summer for C. marksi (P = 0.09) and C. austropalpalis (P = 0.05). Significant geographic variation in abundance was observed for C. marksi, C. austropalpalis and C. dycei with counts decreasing with increasing altitude from the plains to the slopes and tablelands. Culicoides victoriae exhibited the reverse trend in abundance (P = 0.08). Greater abundance during the warmer seasons and at lower altitudes for C. marksi and C. austropalpalis was indicative of temperature and rainfall dependence in this region with moderate summer dominance in rainfall. The Shannon-Wiener diversity index of species was higher on the tablelands (H = 1.59) than the slopes (H = 1.33) and plains (H = 1.08) with evenness indices of 0.62, 0.46 and 0.39 respectively. Culicoides species on the tablelands were more diverse than on the slopes and plains where C. marksi and C. austropalpalis dominated. The temporal and spatial variation in abundance, diversity and evenness of species reported in this diverse region of Australia provides additional insight into Culicoides as pests and disease vectors and may contribute to future modelling studies.

Diversity, Abundance and Host Blood Meal Analysis of Culicoides Latreille (Diptera: Ceratopogonidae) from Cattle Pens in Different Land Use Types from Thailand

“…Diversity and abundance of Culicoides species are related to biotic and abiotic environmental factors, such as climatic conditions, the suitability of immature habitats, host types, and host density [40,41]. In this study, we collected biting midge specimens from cattle pens; thus, the sampling sites did not differ in terms of host availability, except for those at the forest edge where additional wildlife animals can potentially be hosts.…”

Outlook on RNAi-Based Strategies for Controlling Culicoides Biting Midges

“…The seasonality of adult midges is also dependent on species and geography. The common ecological drivers of adult Culicoides abundance include warm springs and autumns, higher precipitation, humidity, proximity to aquatic sources, and proximity to hosts such as cattle and sheep [19][20][21][22]. Evaluating midge abundance is accomplished primarily by trapping adult insects using carbon dioxide-baited traps, light traps, or combinations of these [23].…”

Environmental and Historical Determinants of African Horse Sickness: Insights from Predictive Modeling

“…These elements contribute to the creation of suitable habitats for vectors, thereby influencing the distribution and intensity of AHS outbreaks. Research has pinpointed various land cover types, such as urban areas, croplands, and herbaceous tree shrubs, as conducive environments for AHS vectors, with these habitats being significantly influenced by alterations in altitude and land cover (34)(35)(36). Additionally, the transportation and trade networks of horses are considered crucial in the dissemination of AHS (37,38), highlighting the importance of stringent quarantine measures in horse movement.…”