Induced host-odor mixture imbalance as a method to diminish the attractiveness of a host to harmful insects: a study on the Chagas vector Triatoma infestans

MARTÍNEZ BENINGAZA, ANDREA; DI BENEDETTO INGRID MARIA DESIREE; BABINO, LUCIA; GUERENSTEIN, PABLO

Buenos Aires

Congreso; VII Congress of the Latin American Association of the Chemical Ecology; 2023

Latin American Association of Chemical Ecology

Triatoma infestans, a vector of Trypanosoma cruzi, etiological agent of Chagas disease, is the target ofcontrol programs aiming at interrupting vectorial transmission. Due to the development of resistance toinsecticides, new alternatives for the control of the bugs are needed. We hypothesized that by altering thenatural proportion of a vertebrate odor mixture, the host will be less attractive to T. infestans. Here, weevaluated the attractivity of host odors effect of nonanal in the reduction of attraction to host odors. Weindividually tested 3rd-instar nymphs in dual-choice trap olfactometers during a single night. We evaluatedthe behavioral response of the bugs towards the odor of a mouse, the host (H) and an attractive synthetichost-odor mixture (SOM, consisting of L-(+) lactic and valeric acids, plus ammonia). Doses of nonanal, ina filter paper strip, were incorporated to the odor of H and SOM as follow: D0=0mg, D1=0,2mg; D2=2mgand D3=5mg. In addition, nonanal alone and a control (C-) without any odor were also tested. We calculatedthe percentage of bugs captured (%C) in each treatment. Whereas H+D0 captured 71% of the bugs, H+D1and H+D2 captured 62% and H+D3 38%. In addition, whereas SOM+D0 captured 48% of the bugs,SOM+D1 captured 14%, SOM+D2 24% and SOM+D3 19%. The C- captured no bugs whereas the nonanaltreatments at the three doses tested captured 10-14% of the tested bugs. For the host, the dose of nonanalsignificantly affected the capture, mainly due to the effect of D3. Our work shows that increasing theproportion of nonanal in the natural host-odors mixture results in a decrease in the attraction of T infestanstowards the host, even when nonanal is somewhat attractive by itself. In the case of our synthetic host-odormixture, attraction also was diminished by nonanal, even when this compound was not originally present inthe mixture.