Description of Culicoides truuskae sp. n. (Diptera: Ceratopogonidae) from southern Africa

Culicoides truuskae Labuschagne and Meiswinkel sp. n. is described and illustrated in both sexes from material collected in South Africa and Namibia. It is restricted to the xeric western margin of the subcontinent, occurring in Fynbos, Nama-Karoo and Succulent Karoo ecoregions in South Africa and Desert and Savanna ecoregions in Namibia experiencing 600 mm of rainfall annually. Culicoides truuskae sp. n. is part of the Afrotropical ‘plain-wing’ Culicoides in which the wing lacks a distinguishing pattern of light and dark spots; the diagnostic dark smudge that traverses wing cell r3 may result in C. truuskae sp. n. being misidentified as the sympatric but phyletically unrelated Culicoides herero (Enderlein) – (of the Similis group, subgenus Oecacta Poey). Additionally, this study is the first description of the male of C. herero. C. truuskae sp. n. and Culicoides coarctatus Clastrier and Wirth share similar characters in the male genitalia, although the two species are separable on wing pattern and female flagellum sensilla coeloconica (SCo) distribution. The breeding habitat and adult female blood-feeding preferences of C. truuskae sp. n. are not known. A maximum likelihood phylogenetic tree, using mitochondrial cytochrome c oxidase I (COI) sequence data, is provided to further clarify the relationship between C. truuskae sp. n., C. coarctatus and C. herero. Extensive light trap data, collected over 30 years, are used to map the distribution ranges of C. truuskae sp. n., C. coarctatus and C. herero in Southern Africa. Contribution: The description of this new species and the description of the male of C. herero increases our understanding of the diversity and distribution of Culicoides species in southern Africa

Culicoides species composition and environmental factors influencing African horse sickness distribution at three sites in Namibia

African horse sickness (AHS) is one of the most lethal infectious, non-contagious, vector-borne disease of equids. The causative agent, African horse sickness virus (AHSV) is transmitted via Culicoides midges (Diptera: Ceratopogonidae). AHS is endemic to Namibia but detailed studies of Culicoides communities and influencing environmental parameters are limited. This study aims to determine the Culicoides species composition at three different sites and to assess environmental parameters influencing the geographical distribution of AHS in Namibia. Weekly collections of Culicoides were made during the AHS peak season from January to May for 2013 and 2014 using the Onderstepoort 220 V UV-light trap. Out of 397 collections made, 124 collections (3287 Culicoides) were analysed for AHSV presence with RT-qPCR. A total of 295 collections were analysed for total Culicoides (all collected Culicoides individuals) and in 75% of these collections the Culicoides were identified to species level. C. imicola was the dominant species with proportional representation of 29.9%. C. subschultzei, C. exspectator and C. ravus each contribute more than 10% to the species composition. The lowest number of Culicoides was collected at Aus 9980, a total of 21819 at Windhoek and the highest number at Okahandja 47343. AHSV was present at all three sites during 2013 but only in Windhoek and Okahandja during 2014. Multivariate analyses of data from the two year survey indicate the environmental parameters in order of importance for the distribution of AHS in Namibia as precipitation > temperature > clay > relative humidity > NDVI. The implication of these findings is that any precipitation event increases Culicoides numbers significantly. Together with these results the high number of species found of which little is known regarding their vector competence, add to the complexity of the distribution of AHS in Namibi