Résumé des résultats (Abstract)
(Anglais)
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Triatomine bugs are vectors of Chagas disease in Central and South America. The ECLAT research network aims to provide biotechnical support to control programmes. The University of Neucâtel has a role in the area of sensory and behavioural physiology of triatomines. The primary research area is to understand how silvatic triatomine species succeed in colonizing peridomestic and domestic habitats
Triatomines seek birds and wild mammals, or man and his domestic animals for a blood-meal from nearby refuges. In the absence of other sensory stimulation, triatomines are attracted to a variety of host odours (Refs. 1 & 2). This capacity to modify the behaviour of triatomines with chemicals provides a promising avenue for the developement of traps baited with attractants to survey triatomine populations around dwellings. During this project our studies have concentrated on olfaction in triatomines and the behavioural responses of the bugs to odours.
Olfaction in triatomines Scanning and transmission electron microscopy examination of triatomine antennae show that odours are perceived via an array of olfactory receptors in wall-pore and grooved-peg olfactory sensilla (Diehl et al., in prep.). Electrophysiological recordings show that these receptors respond to host odour extracts, and to short-chain carboxylic acids, aliphatic aldehydes, ammonia and plant volatiles (Refs. 2 - 6).
Attraction to host odours Triatomine bugs are attracted to host odours on a locomotion compensator. (Refs. 1 - 6). Some volatile products occur in both host odours and in the odours of triatomines and their excreta. So it would appear that triatomines make parsimonious use of such products as an odour cue for host finding and in the detection of well frequented refuges where the odours of conspecifics and their excreta abound. Our challenge in the next phase of the work is to develop mixtures of attractants with which to lure the triatomines into traps.
References
1.Taneja J. and Guerin P.M. (1995). Oriented responses of the triatomine bugs Rhodnius prolixus and Triatoma infestans to vertebrate odours on a servosphere. Journal of Comparative Physiology A 176, 455-464.
2. Taneja J. (1996). Sensory and behavioural responses of Rhodnius prolixus and Triatoma infestans to vertebrate odours and to volatiles from triatomin faeces. Ph. D. thesis, Univsersity of Neuchâtel.
3. Taneja J. and Guerin P.M. (1997). Ammonia attracts the heamatophagous bug Triatoma infestans: behavioural and neurophysiological data on nymphs. Journal of Comparative Physiology A 181, 21-34.
4. Guerenstien P.G. (1999). Sensory and behavioural responses of Triatoma infestans to host and conspecific odours. Ph. D. thesis, University of Neuchâtel.
5. Guerin P.M., Kröber T., McMahon C.P., Guerenstein P., Grenacher S., Vlimant M., Diehl P.A., Steullet P. and Syed Z. (2000). Chemosensory and behavioural adaptations of ectoparasitic arthropods. Nova Acta Leopoldina 83, 197-213.
6. Guerenstein P.G. and Guerin P.M. (2001). Olfactory and behavioural responses of the blood-sucking bug Triatoma infestans to odours of vertebrate hosts. Journal of Experimental Biology 204, 585-597.
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