AGGREGATION IN THE HEMATOPHAGOUS BUG TRIATOMA-INFESTANS - CHEMICAL SIGNALS AND TEMPORAL PATTERN

Triatominae bugs remain quiet during the day, when they can be usually found assembled in protected sites, becoming active at night. By means of olfactometers and in different experimental arenas, we studied in the laboratory the response of Triatoma infestans (Klug) to volatiles present in their faeces and the dynamics of the aggregation behaviour. In a choice arena, nymphs showed a significant tendency to aggregate around papers impregnated with dry faeces. In a simultaneous discrimination olfactometer, an air current passed by a paper impregnated with dry faeces also elicited a significant attraction. Freshly deposited faeces did not elicit attraction, but rather a significant rejection was observed. Immediately after feeding, insects did not prefer impregnated papers and were randomly distributed in the arena. The change in the response from indifference to attraction takes place within the first 24 h after feeding. Finally, a spontaneous daily rhythm of aggregation/dispersion was demonstrated from the 6th day after feeding onwards. Maxima of assembling and dispersion occur at the onset of the photophase and scotophase, respectively.