Blood-feeding performance of nymphs and adults of Triatoma brasiliensis on human hosts.

The blood-feeding behaviour of nymphs and adults of Triatoma brasiliensis fed on the forearm of human volunteers was studied by electronic monitoring of the cibarial pump. Parameters of total contact time (TT), initial weight (IW), weight gain (WG), ingestion rate (IR), pump frequency (F), quantity of liquid ingested per cibarial pump stroke (QLC) and non-ingestive time (NIT) (cumulative probing time and pumping interruptions during blood feeding) were measured. Protein profile (SDS-PAGE) and quantity of proteins of salivary gland extracts (QP) were also determined for each stage. The TT reflects the feeding performance of the insects and differed between instars, varying between 18.3+/-2.5 min for the first instar and 33.9+/-2.3 min for the fifth instar. The observed increase in the IR when comparing different instars was related to the increase in the cibarial pump volume inferred from the QLC data. During development, the volume of the cibarial pump grew asymmetrically determining the different contact times observed among the instars. Males and females presented a remarkable sexual dimorphism in respect to the volume of the cibarial pump, females showing a better performance compared to males. Despite the differences, the results show that each of the development stages of T. brasiliensis was able to obtain a relatively fast bloodmeal, with few interruptions and without causing pain, providing further evidence of the capacity of this species to adapt to domestic environments.