Compounds released by disturbed adults of the haematophagous bug Triatoma infestans (Hemiptera: Reduviidae): behavioural effects of single compounds and binary mixtures

Abstract

Adults of the Chagas disease vector Triatoma infestans Klug (Hemiptera: Reduviidae: Triatominae), possess paired exocrine glands: the metasternal and Brindley's glands. Both glands are discharged by disturbed adults, releasing an alarm pheromone that elicits an escape response of larvae. The present study analyzes the individual (or combined) effects of some of the volatiles of the whole pheromone blend released under disturbance, searching for active compounds and for possible interactions (e.g. synergism, additive effects) between them. Using an experimental arena, different doses of components emitted by disturbed adults are tested against larvae. Larvae show escape responses to some of the acids, as well as to one alcohol, but no response to ketones. This is observed with certain doses of compounds from Brindley's glands (isobutyric, butyric and acetic acid; 2‐methyl‐1‐butanol), although the compounds tested in the present study that are produced by metasternal glands are shown to evoke random responses, suggesting that mainly Brindley's glands are involved in the alarm context. Two combinations of two individually repellent compounds (2‐methyl‐1‐butanol with acetic or isobutyric acid) evoke escape responses, although other combinations make the individual effect disappear. A different mixture of two individually repellent compounds (butyric and isobutyric acid) evokes attraction, although these are also host odours. The potential use of the active compounds released by disturbed adults to monitor triatomine populations is discussed.