Phylogenetic analysis indicates that Culicoides dewulfi should not be considered part of the Culicoides obsoletus complex.

Analysis of DNA sequence data has proven invaluable for defining the relationships among taxa, as well as resolving their evolutionary histories. Here, we analyzed DNA sequence variation of one mitochondrial gene (COI) and two nuclear regions (ITSI and II) to clarify the phylogenetic position of Culicoides dewulfi, a midge species widely spread in Europe and a suspected vector for bluetongue virus. Various authors have described C. dewulfi either as part of the Culicoides obsoletus sensu lato complex or as a separate taxonomic group. A maximum likelihood phylogeny, based upon an optimal model of sequence evolution, placed C. dewulfi outwith the C. obsoletus s.l. complex. Shimodaira-Hasegawa test highlighted that this topology was significantly more likely than any topology that placed C. dewulfi anywhere else in the phylogeny. As such, C. dewulfi should not be considered part of the C. obsoletus s.l. complex and instead be treated as a separate group, phylogenetically close to the classical Old World vector C. imicola.

Identification of bloodmeals of the Scottish biting midge, Culicoides impunctatus, by indirect enzyme-linked immunosorbent assay (ELISA).

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed to identify the bloodmeal sources of Culicoides impunctatus Goetghebuer. Nightly light trapping in Scotland, between April and September 1992, caught a total of 344 blood-engorged female C. impunctatus, all in May, June and July. The insects were stored in 70% ethanol and tested 5-7 months later. Bloodmeal sources were positively identified for 246 (71.5%). Bovine hosts were most common (38.4%), followed by deer (23.0%) and sheep (9.9%). Only one midge had fed on human blood. Relatively freshly fed (< 24 h), fully engorged females gave the clearest results. The wider applications of the technique to the study of Culicoides host preferences is discussed.

Morphology of the antennae of two species of biting midge: Culicoides impunctatus (Goetghebuer) and Culicoides nubeculosus (Meigen) (Diptera, Ceratopogonidae).

Scanning and transmission electron microscopy of the antennae of Culicoides impunctatus and Culicoides nubeculosus show that males and females share five sensillum types. Sensilla chaetica resemble mechanoreceptors, each innervated by a single neurone whose dendrite terminates distally in a tubular body: the arrangement of sensilla on male antennae suggests that females are located by sound. The antennae have both sharp- and blunt-tipped sensilla trichodea, sharp-tipped sensilla on only the distal third and blunt-tipped sensilla on all subsegments. These sensilla are typical of olfactory receptors, having multiporous walls and being innervated by a number of neurones with bifurcating dendrites ascending the hair shafts. Sensilla basiconica occur on the distal five subsegments of the female antenna and the distal three subsegments of the male antenna. Sensilla coeloconica always occur on subsegment one and sometimes on a number of other subsegments, depending on sex and species. Both basiconic and coeloconic sensilla have double walls and unbranched dendrites and may be either olfactory or thermo- and/or hygroreceptors. All antennae except those of male C. impunctatus antennae have sensilla ampullacea, apparently deep-seated olfactory or thermoreceptors. Small peg sensilla fitting the description of contact chemoreceptors occur only at the tip of the male antenna.