Distribution of the genus Culi(;oid::s (Diptera: Ceratopogonidae) along the and its tributaries :n Flanders with special attention for the pest species Culicoides riethi

1 2 Charlotte SOHIERI.2, Wouter DEKONINCK ' , Veerle VERSTEIR-f, lsra DEBLAUW~, Frederik HENDRICKXI. 2 & Patrick GROOTAERT1

1 Royal Belgian Institute of Natural Sciences (RBINS), Entomology Department, Vautierstraat 29, B-1000 Brussels (e-ma il: [email protected]) 2 University Gent, Research Unit Terrestrial Ecology, Biology Department, K.L. Ledeganckstraat 29, B-9000 Gent 3 Institute of Tropical Medicine, department Parasitology (unit Entomology), Nationalestraat 155, B-2000 , . 4 Institute of Tropical Medicine, departement Animal Health, Kronenburgstraat 25, B-2000 Antwerp

Keywords: Culicoides, pest species, faunistics, Sea Scheldt, Culicoides riethi.

Introduction Culicoides, has been implemented. Within this context the following research Culicoides or biting midges are worldwide goals were addressed: (1) Exploration of the best known as vector of viruses pathogenic for Culicoides diversity and species distribution various mammals. T hey can also transmit patterns in the region of the Sea and Upper roundworms and protozoa in birds, humans and Scheldt and its tributaries to gain a better other animals. The females of Culicoides species understanding based on the collected data and suck blood from warm-blooded animals. As they literature; (2) Getting insight in the biology and often occur in swarms, they can be a nuisance to lifestyle of the nuisance species C. riethi in humans, especially for people that react allergic Gentbrugge, with the purpose of highlighting to their bites. Despite their importance, little is measures to reduce its nuisance; (3) Analysis of yet known about the biology and ecology for the the efficiency of the two traps used, the Mosquito majority of the species. They are moreover often magnet Liberty P lus (MMLP) and the CDC light difficult to distinguish based solely on trap by experimental design. morphological traits such that molecular identification tools are recommended. Results and discussion This master proof was part of the ongoing project "MODIRISK (2007-2011): Mosquito A total of 1244 Culicoides were counted in the vectors of disease: spatial biodiversity, drivers of 85 examined MODIRJSK samples located along change and risk" (www.modirisk.be). Emphasis the Sea- and Upper Scheldt. 17 o f the 45 was on the distribution of the genus Culicoides Culicoides species recorded until now in along the Sea and Upper Scheldt. A detailed Belgium (DEBLAUWE et al., 2009) were found in study investigated the biology and ecology of the the MMLP catches during the period 2007-2008. species Culicoides riethi K IEFFER, 1914, which The following species were most abundant: recently caused severe annoyance in Gentbrugge Culicoides chiopterus (MEIGEN, 1830), (VERSTEIRT et al., 2009). Furthem1ore an Culicoides dewulfi GOET I-I GEBUER, 1936, C. experiment with Forcipomyia sp., related to riethi, Culicoides obsoletus (MEI GEN, 1818) I

141 Culicoides scoticus DOWNES & CATTLE, 1952 A major conclusion from this. thesis is that complex and Culicoides puncta/us {MEIGEN: ~-;~ore research on the biology and habitat 1804). The sub genus Avaritia, with the followint! :-equirements of this species is necessary to 4 species: C. chiopterus, C. obsoletus, C. :•rovJde insight and solutions to reduce the scoticus and C. dewulfi, was capwred moc;t nuisance in Gentbrugge. frequently. Moreover C. chiopterus and C. Results in the larval experiment with obsoletus-scoticus complex often appeared to be Forcipomyia sp. under different treatments at the same site; whilst C. riethi and C. indicate that this species does not hatch after a obsoletus-scoticus-complex were rarely found treatment of 15 days submerged. This in contrast together. to the reference treatment and a submergence The MMLP appeared to be an effective system treatment of 6 days where a large number of for trapping Culicoides, with females being larvae hatched. However, even in the dry caught in higher densities than males. treatment some individuals of Forcipomyia sp. Concerning the nuisance causing species in were able to hatch. Also we found a positive Gentbrugge, identification of specimens revealed correlation between the organic matter and the that it belongs to the species C. riethi. This amount of hatched Forcipomyia sp. species belongs to the subgenus Monoculicoides. Already between 1920-1930 this species was Acknowledgements present in Hamrne along the Durme (specimens present in the KBIN collection of Goetghebuer). This work was funded by the Belgium government Literature search revealed that this species is yet (Belspo; SD/BD/04A) (MODIRISK), by the city of (CULIMON Deelluikl) and by the Flemish present for a long time in and around the Sea Administration for Waterways and Maritime Affairs, Scheldt and its tributaries. division Zeeschelde (CULIMON Deelluik 2; project Further research showed higher densities of C. nr. 16El/09/41). We want to thank Viki Vandomme riethi closer to the Sea Scheldt. There were from the Research Unit Terrestrial Ecology, however also remarkably high populations more University Gent for her assistance in the field and the than 100 meters away from the Sea Scheldt. A laboratory. clear reason for this observed pattern could not yet be given. References During the inventory, C. riethi was caught with two different trapping systems. DEBLAUWE 1., DE DEKEN G., MADDER M., DE DEKEN Compared to the CDC light trap, the MMLP R., FASSOTTE C., CORS R., LOSSON B., caught four times more C. riethi during the PATERNOSTRE J., HAUBRUGE E. & SIMONON G., 2009, - Culicoides diversity in Belgium and some peak flight activity of the species. Both taxonomic problems, Minutes of the Med.ReoNet trapping systems collected mainly female C. taxonomy meeting Strasbourg, 16-20 March 2009, riethi. p4. C. riethi clearly showed an activity peak VERSTEIRTV., DEKONINCK W., SOHIER C., MAELFAIT during dawn and smaller peaks during dusk. J.P., DEBLAUWE 1., VAN BORTEL W., GROOTAERT Based on the two larval studies of C. riethi, it P., 2009.- Nematocera overlast aan de Zeeschelde is indicated that the larvae of C. riethi occur in Gent, eindverslag, 19 pp. locally high concentrations.

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