Distribution of Culicoides biting midges (Diptera: Ceratopogonidae) in southern Australia and insight into the Culicoides victoriae morpho‐variants

Abstract

AbstractCertain Culicoides species (biting midges) are important vectors globally of a range of viruses, protozoa and filarial parasites, imposing a significant economic and health burden. In a changing climate, understanding which Culicoides species occur in a region is important for biosecurity risk management. We examined the occurrence of predominant Culicoides species in south‐east Australia and provide insight into five Culicoides victoriae morpho‐variants. Culicoides were surveyed using Centre for Disease Control light traps and Yellow Sticky traps, with identification performed morphologically and molecularly. Two polymerase chain reaction – restriction fragment length polymorphism (PCR‐RFLP) assays based on mitochondrial cytochrome c oxidase subunit I were developed to differentiate morphologically similar C. victoriae, with a subset sequenced for nuclear carbomoylphosphate synthase. The structure of the five C. victoriae morpho‐variants was investigated through phylogenetic trees, haplotype networks and the Barcode Index Number system (BINs) in the Barcode of Life Data (BOLD) database. Twenty‐five different Culicoides species were identified in the sampled region with Culicoides austropalpalis, C. victoriae, C. marksi and C. molestus Gp sp No 2 being the most common. Two PCR‐RFLP assays were developed using either one or three enzymes, with a 90% or 99% success rate, respectively, of being able to differentiate the five C. victoriae morpho‐variants. Mitochondrial and nuclear sequence divergence supported by wing patterning allowed the recognition of multiple potentially new species of C. victoriae and identified species in uncharacterised regions.