Preliminary evidence of triatomine host-seeking behavior modulation by a new repellent of bacterial origin.

RAMIREZ MELANIE; ORTIZ MARIO; GUERENSTEIN P.G.; MOLINA JORGE

Congreso; 5th Meeting of the Latin American Association for Chemical Ecology,; 2018

The host seeking behavior of hematophagous insects is highly associated with the volatileorganic compounds (VOCs) released by the host. The attractive and non-attractive role ofVOCs produced by bacteria from human skin has been previously shown in the kissingbug Rhodnius prolixus (Ortiz et al. 2011, Tabares et al. 2018).The aim of this study was to assess the behavioral responses of R. prolixus and Triatomainfestans to previously identified VOCs produced in vitro by non-attractive bacterialspecies, isolated from human skin. Using an exposure device, we evaluate the repellencyeffect of three compounds, at different concentrations, by quantifying both, the time spentin the host proximity and the number of proboscis extension reflex (PER). These resultswere compared with the control (e.g. host without the presence of the repellentcompound) and the gold standard DEET. Additionally, a capture olfactometer were usedto assess the percentage of total captures and oriented captures of Rhodnius prolixus inthe presence of one of the repellent compounds during a whole night test.In the presence of one of the compounds, Rhodnius prolixus and Triatoma infestanssignificantly reduces the time spent in the host proximity as well as the number of PER.The concentration at which the same repellent effect is achieve is around ninety timeslower than DEET. In the same way, the percentage of total captures and oriented capturesin the presence of the tested compound were lower than the control experiment forRhodnius prolixus.The behavioral evidence presented here reinforces the idea that VOCs produced bybacteria can modulate the host seeking behavior of R. prolixus and T. infestans. Futureefforts should be oriented to evaluate these compounds in field tests.Ortiz MI, Suarez-Rivillas A, Molina J. (2011) Behavioural responses to human skinextracts and antennal phenotypes of sylvatic first filial generation and long rearinglaboratory colony Rhodnius prolixus. Memorias Instituto Oswaldo Cruz. 106(4):461-466.Tabares M, Ortiz M, Gonzalez M, Carazzone C, Vives Florez MJ, Molina J (2018)Behavioral responses of Rhodnius prolixus to volatile organic compounds released invitro by bacteria isolated from human facial skin. PLoS Neglected Tropical Diseases 12(4): e0006423.Acknowledgements: Convocatoria Nacional Doctorado No. 567-Colciencias andProyecto semilla-Facultad de Ciencias, for financial support.