Orientation behaviour of Culicoides obsoletus (Diptera: Ceratopogonidae), a relevant virus vector in northern Europe, toward host-associated odorant cues

Abstract

a b s t r a c tSome Culicoides biting midge species (Diptera: Ceratopogonidae) are biological virus vectors worldwide and have recently been associated with outbreaks of important epizootic diseases such as bluetongue and Schmallenberg in northern Europe. These diseases, which affect domestic and wild ruminants, have caused considerable economic losses. Knowledge of host preferences of these biting midges -especially of the relevant vectors of arboviruses near farms, such as Culicoides obsoletus in northern Europe -is essential to understand pathogen transmission cycles and the epidemiology of associated diseases. This study aimed to determine host preferences of C. obsoletus using an in-field flight tunnel containing pairs of calf, sheep, chicken, and human hosts (and controls) and a laboratory two-choice bioassay containing volatile extracts of host skin (and controls). Behavioural responses of nulliparous C. obsoletus females in the in-field flight tunnel showed a preference for human (but also calf and sheep) hosts, probably due to their exhalation of greater quantities of carbon dioxide. The laboratory experiment revealed that volatile organic compounds released from the skin of chicken and sheep seemed to attract this species. Culicoides obsoletus, thus, seems to have a wide host range and to be particularly attracted by humans under field conditions. A better understanding of vector-host interaction could enable the development of control strategies against adult biting midges, by exploiting insect-repelling or -attractive semiochemicals. Volatile extracts of chicken and/or sheep skin could be used to identify volatile compounds attractive to C. obsoletus, which in turn could be used in baited traps.

Association between host species choice and morphological characters of main sensory structures of Culicoides in the Palaeartic region

“…The ornithophilic species show a number of sensilla coeloconica ranging from eight to 13. The morphological sensillum types of antenna and host preference were not associated with their phylogenetic relationship ( Isberg, Hillbur & Ignell, 2013 ) but rather with volatile organic compounds, captured by different receptors present on sensillum types ( Zimmer et al, 2015 ).…”

“…Semiochemicals can provide information about the location, suitability, or physiological state of conspecifics, hosts, or breeding sites ( Logan & Birkett, 2007 ). Moreover, several studies carried out on feeding patterns of biting midges found variation in host attractiveness to be correlated with exhaled carbon dioxide (CO 2 ), 1-octen-3-ol, lactic acid, acetone ( Zimmer et al, 2015 ), specific phenolic compounds emitted from urine, ( Bhasin, Luntz & Mordue, 2001 ) or hair fragrance ( Mands, Kline & Blackwell, 2004 ).…”

Serological Study of Exposure to Selected Arthropod-Borne Pathogens in European Bison (Bison bonasus) in Poland

“…In case of domestic ruminants, SBV seroprevalence was also higher in cattle than in small ruminants (Larska et al, 2014a), which may be explained by the lower dose of SBV necessary to produce an infection in bovids comparing to sheep, which would need a 10-fold virus dose to seroconvert (Wernike et al, 2012;Poskin et al, 2014). Furthermore, larger hosts excrete more carbon dioxide and 1-octen-3-ol, the volatile attractants for haematophagous midges, which may increase the risk of the exposure to vector-borne pathogens (Koch and Axtell, 1979;Zimmer et al, 2015). As shown by Viennet et al (2013), midges prefer to feed on the largest hosts available in the environment.…”

Infectious Disease Monitoring of European Bison (Bison bonasus)

“…Most probably, higher exposure in larger ruminants is associated with their higher production of carbon dioxide, one of the strongest attractants of many arthropods including Culicoides spp. [79,80]. SBV in utero infections may lead to congenital malformations of newborns, stillbirths, or abortions.…”