A methodological study to assess attraction and trapping in vectors of Chagas disease

GARCIA MAILEN; BRATOVICH C; GUIDOBALDI F; GUERENSTEIN PG

Huerta Grande - COR

Congreso; 2nd Meeting of the Latin American Association for Chemical Ecology; 2012

Asociacion Latinoamericana de Ecologia Quimica, CICYTTP-CONICET, Fac. Agronomia-UBA

The most effective strategy to prevent Chagas disease is by vector control [1],and one sustainable, environmentally-friendly, method for this is the use of trapdevices lured with attractants. To find out effective attractants, differentolfactometers were previously used, in which attraction is quantified as walkingdisplacement towards a test zone. In our laboratory we are using a dual-choicetrap olfactometer [2], consisting of an arena with 3 holes. A tube is connectedfrom below to each hole and the arena can virtually be divided in 3 zones: neutral(where a “refuge” –starting point- tube is connected; this is the only tubecontaining a piece of cardboard to allow insects reach the arena), test andcontrol, each with a hole to which a trap-tube is connected. The test and controlzone, opposite to the neutral zone, are separated by a partition. Below the “testtrap-tube” a test odor source is placed, whereas below the “control trap-tube” theodor control is placed. A single insect is tested overnight. Attraction is quantifiedin terms of number of insects trapped in the control and test tubes. By videorecordingthe experiments, we could for the first time: 1) compare our trappingresults with results obtained measuring attraction in other ways; 2) study thebehavior dynamics preceding trapping. Two stimuli (mouse and a synthetic odorblend) were tested in Triatoma infestans and Rhodnius prolixus. An analysis ofthe insects’ first choice (i.e., test or control side) after leaving the refuge suggeststhat in our device this way of measuring attraction may overestimate results in R.prolixus when comparing to capture data. Capture occurred mainly during the firsthalf hour of experiment. The two stimuli caused the insects to spend less time inthe neutral zone than in tests in which there was no odor stimulus below eithertrap-tube.[1] WHO, 2010. Chagas disease (American trypanosomiasis). Fact sheet N°340.http://www.who.int/mediacentre/factsheets/fs340/en/index.html[2] Guerenstein P. G., Lorenzo, M. G., Núñez J. A. and Lazzari C. R. 1995.Bakers-yeast, an attractant for baiting traps for Chagas-disease vectors.Experientia 51, 834-837