Attraction of mosquitoes to volatiles associated with blood

Abstract

Responses of the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Culex nigripalpus to volatiles and compounds associated with bovine and avian blood that were presented in collagen membranes were evaluated in olfactometer and landing assays. The presence of attractants produced by blood was supported by more attraction of all species to blood than water controls in the olfactometer. Females of Ae. aegypti and Cx. quinquefasciatus were more attracted to bovine blood than to avian blood, but there was no difference in Cx. nigripalpus responses. In landing assays, significantly more females of all species landed on casings with blood than on water controls. There was no difference in landing of Ae. aegypti on bovine or avian blood. However, significantly more females of Cx. quinquefasciatus and Cx. nigripalpus landed on avian blood compared to bovine blood. Blood presented in collagen casings was an effective method for evaluating in-flight attraction and landing in all three species. In the olfactometer, several individual compounds elicited attraction in all species, but none were as attractive as blood for all species. In landing assays, several organic acids and sulfides elicited landing, with Ae. aegypti responding to the greatest number of compounds. These assay methods are effective for evaluation of volatile compounds from blood, and although responses were obtained to several compounds, none were as effective as blood in the olfactometer and landing assays.

Olfactory and behavioural responses of tsetse flies, Glossina spp., to rumen metabolites

“…Moreover, dimethyl trisulphide elicited increased landing by Culex quinquefasciatus and Cx. nigripalpus on a collagen casing treated with this compound (Allan et al 2006) and attraction of S. calcitrans in a wind tunnel (Jeanbourquin and Guerin 2007), Cx. tarsalis to sticky traps (Du and Millar 1999) and seven species of Calliphoridae to traps baited with this substance (Nilssen et al 1996).…”

Olfaction in vector-host interactions

“…Propanoic, butanoic, 3-methylbutanoic, pentanoic, heptanoic, decanoic, dodecanoic, tetradecanoic, pentadecanoic, hexadecanoic, heptadecanoic, and octadecanoic acid did not attract Ae. aegypti females, even though some of these acids were present at higher levels in the skin emanations of highly attractive persons (Allan et al 2006a. Propanoic and pentanoic acid did not influence the attractiveness of CO 2 .…”

“…aegypti were found to be attracted to the odour of bovine and avian blood. Culex females landed more on membranes filled with avian than with bovine blood, whereas Aedes mosquitoes showed no landing preference (Allan et al 2006a). The volatile chemicals emanating from blood have been identified (Ashley et al 1992, Issachar et al 1982, Sastry et al 1980) but few of these have been tested for their effects on mosquitoes in the laboratory, although components found in exhaled breath and skin emanations may be similar to those present in blood (Sastry et al 1980).…”

“…aegypti females and to elicit a landing response. Several other carboxylic acids, including two aromatics, induced landing responses (Table 1) (Allan et al 2006a). In contrast, hexanoic acid reduced the number of landings (Douglas et al 2005), probably due to the high doses used.…”

“…aegypti (Table 1) , Smith et al 1970. Lactic acid is a weak attractant on its own but acts synergistically with carbon dioxide (CO 2 ), a major component of exhaled breath, and other volatiles emanating from human skin , Allan et al 2006a,b, Smith et al 1970, Williams et al 2006a). An ethanol extract of human skin was no longer attractive to Ae.…”