Orientation behaviour of the blood-sucking bug Triatoma infestans to short-chain fatty acids: synergistic effect of L-lactic acid and carbon dioxide.

BARROZO RB, LAZZARI CR.

Chemical Senses

OXFORD JOURNALS

Año: 2004 vol. 29 p. 833 - 841

0379-864X

The role of short-chain fatty acids in the host-seeking behaviour of Triatoma infestans larvae was investigated using a locomotion compensator. Several short-chain fatty acids were tested alone over a wide range of doses, or in combination with L-lactic acid (100 mg). Bugs showed no attractive response to single carboxylic acids, but when L-lactic acid (L-LA) was added to airstreams carrying specific intensities of either propionic (C3; 100 mg), butyric (C4; 1 mg) or valeric acid (C5; 1 mg), they became attractive, evincing a synergistic effect. No orientation response was observed when caproic acid (C6) was offered with L-LA at the doses tested. Two blends were arranged: (1) C3, C4 and C5 combined at the effective doses when added with L-LA [C3C4C5 (1)], and (2) C3, C4 and C5 combined at a third of those intensities [C3C4C5 (2)]. Both blends were tested alone, with L-LA (100 mg), with a sub-threshold concentration of CO2 (300 p.p.m. above the ambient level), and combined with both compounds together. Oriented responses of bugs were only observed with the blend (2) added with L-LA and with the combination of this lure with CO2. This last combination evoked a behavioural response similar in intensity to that induced by a live mouse.