[Feeding preferences in 3 species of Triatominae (Hemiptera: Reduviidae) in experimental conditions]

Feeding preferences of three species of triatomines (Triatoma infestans, T. dimidiata, and Rhodnius prolixus) on four vertebrate hosts (opposum, dog, chicken and toad) were studied in a specially designed cage during daylight (2 hours) and at night (14 hours). T. infestans and R. prolixus remained close to the host after feeding, while T. dimidiata wandered a short distance away, apparently for protection against preying by the host. R. prolixus showed the lightest values of ingestion in relation to its own weight. The amount of blood ingested by the three species was not related to the type of host. The percentage of insects that fed during the short and long periods of exposure, and the amount of blood ingested were similar in both experiments. The vertebrate hosts showed no prey preference for any of the three species. All the triatomines exhibited a marked preference for the homeothermic hosts, only a very small percentage (0.7%) of T. dimidiata, the least aggressive of the three species, fed on the toad; the insects that fed on two or more hosts did not exceed 8.1% T. infestans showed a slight preference for dogs. During nocturnal experiments all three species preferred to feed on hosts that slept at this time.