A comparison of volatiles emitted by adults of three triatomine species.

GUERENSTEIN PG; GUERIN PM

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2004 vol. 111 p. 151 - 155

0013-8703

Brindley’s gland exocrine secretion from adult triatomines is considered an ‘alarm pheromone’. This secretion and the headspace over disturbed adult Triatoma infestans consist of a mixture of carboxylic acids including isobutyric acid (mixture A). However, recently, Brindley’s gland secretion, and the headspace over disturbed adult T. infestans was reported to contain isobutyric acid, plus alcohols, esters and aromatic compounds (mixture B). Brindley’s gland secretion of Rhodnius prolixus was found to contain isobutyric acid, other carboxylic acids, and esters (mixture C). We asked if the blend of odours from disturbed adults, supposedly originating in the Brindley’s gland secretion, is characteristic of each species. Different triatomine species were reared and tested under similar conditions. Moreover, we attempted to identify mating-associated odours for R. prolixus. The headspace over disturbed R. prolixus adults consisted of a blend of carboxylic acids including isobutyric acid, similar to mixture A. The mixture identified from disturbed T. infestans .was similar to mixture B. In controlled experiments, the only compound detected in samples over both males alone and mating pairs of undisturbed R. prolixus was isobutyric acid. The amount of isobutyric acid from undisturbed R. prolixus was 100-fold smaller than that from disturbed adult R. prolixus. That may suggest that the bugs continuously release low quantities of the acid. Many of the compounds detected are constituents of vertebrate odour. Isobutyric acid induces repellence at high doses and attraction at low doses. A few undisturbed adults could release low levels of acid that may cause the animals to aggregate in a refuge. A parsimonious use of isobutyric acid (and some of the other compounds secreted) by triatomines is proposed: this compound could be used as an alarm signal, a host attractant, and as an intraspecific aggregation signal, depending on the concentration and physiological state of the perceiving bug.