COMPARATIVE KINETICS OF BLOODMEAL INTAKE BY TRIATOMA-INFESTANS AND RHODNIUS-PROLIXUS, THE 2 PRINCIPAL VECTORS OF CHAGAS-DISEASE

Chagas disease vector insects Triatoma infestans and Rhodnius prolixus (fifteen stage III nymphs per 4 litre cage were allowed to feed on an aesthetized mice for Ih !control group), or on active non-anaesthetize d mice (NAM) for 2, 4 or 8 h exposure. The bloodmeal size (weight incr ease) for both species was proportional to the duration of contact wit h NAM. due to ingestion of multiple small bloodmeals, up to 142% of co ntrol weight for T. infestans with 8 h exposure to NAM. The mean weigh t increase of T. infestans nymphs after 4 h contact with NAM was simil ar to that of the control group, whereas for R. prolixus. Sh contact w ith NARI gave only 64% of the control value. For both species of insec t, within 4 h of feeding, >20% of the bloodmeal weight was lost by def aecation and diuresis. The proportions of unfed nymphs and mortality d uring 2 h contact with NAM were significantly higher for R. prolixus, demonstrating better exploitation of the host blood sourer by T. infes tans, apparently because during blood-feeding the latter insect specie s caused less irritation to the host.