Trends in Parasitology
Research FocusNo accounting for taste: host preference in malaria vectors
Section snippets
Genes versus environment
Host preference has been defined as the genetically based tendency to respond to particular host cues [1]. The expression of host preference in Nature is modulated by many variables (e.g. relative host abundance and accessibility). These confounding factors have hindered substantial progress in our understanding of the contribution of the innate component in the process of host selection. Traditional approaches based on the analysis of mosquito bloodmeals or collection rates on alternative
Signal versus noise
Laboratory attempts to study host preference have encountered variable success 7, 8, 9, 10. Constraining factors in the interpretation of results from such studies are the unknown effects of laboratory colonization and maintenance of mosquito strains, and other departures from natural conditions. Field-based experimental approaches appear more promising, but they require appropriate tools and care must be taken to interpret results within the framework of each specific experimental context.
Nature versus nurture
The relatively loud biological ‘noise’ revealed by behavioural studies of host preference helps explain the almost complete lack of progress at understanding its genetic basis. The indications that do exist come from two lines of evidence: polymorphic chromosomal inversions and selection experiments. First, it has been shown that in An. arabiensis, An. gambiae and An. funestus, carriers of certain chromosomal arrangements are preferentially associated with human habitations and therefore have
An outlook for the future
Although mosquito behaviours such as host preference are influenced by the environment, there is an underlying genetic basis. With the appropriate choice of genetic backgrounds and phenotypic assays, ultimately, it should be possible to understand at the molecular and genetic level how olfactory, visual, taste and sound cues operate to trigger behaviours that directly or indirectly impact vectorial capacity, for example, house entry, indoor resting, choice of oviposition site, host finding and
Acknowledgements
Some content of this review is adapted from a more comprehensive treatment of host use in flies, which will appear in K.E. Filchak et al.The ecological genetics of host use in the Diptera. In: The Evolutionary Biology of Flies. (Wiegman, B.M. and Yeates, D.K., eds.), Columbia University Press (in press).
References (25)
Similar feeding preferences of Anopheles gambiae and A. arabiensis in Senegal
Trans. R. Soc. Trop. Med. Hyg.
(1998)Chromosomal differentiation and adaptation to human environments in the Anopheles gambiae complex
Trans. R. Soc. Trop. Med. Hyg.
(1979)The Biology of Mosquitoes
(1999)Mosquito behavioural aspects of vector-human interactions in the Anopheles gambiae complex
Parassitologia
(1999)Anopheles gambiae complex and disease transmission in Africa
Trans. R. Soc. Trop. Med. Hyg.
(1974)- Gillies, M.T. and Coetzee, M. (1987) A Supplement to the Anophelinae of Africa South of the Sahara, Publication no. 55,...
Experiments on host selection in the Anopheles gambiae complex
Ann. Trop. Med. Parasitol.
(1967)Adult behavior of members of the Anopheles gambiae complex in The Gambia with special reference to An. melas and its chromosomal variants
Parassitologia
(1987)L-lactic acid: a human-signifying host cue for the anthropophilic mosquito Anopheles gambiae
Med. Vet. Entomol.
(2002)Innate preference for host-odor blends modulates degree of anthropophagy of Anopheles gambiae sensu lato (Diptera: Culicidae)
J. Med. Entomol.
(2001)