Life history data of a Triatoma protracta nahuatlae, T. sinaloensis, and their laboratory hybrids (Hemiptera:...

Chagas disease is one of the most significant vector-borne diseases in Mexico. The presence of "sylvatic" triatomine vectors of Trypanosoma cruzi (Chagas) inside human dwellings necessitates estimating their vectorial capacity. To estimate this capacity in Triatoma protracta nahuatlae (Ryckman), Triatoma sinaloensis (Ryckman), and their laboratory hybrids, 6 biological parameters were examined. Triatoma sinaloensis exhibited the shortest development time (155 days), with a median of 12 blood meals. Mortality rates varied from 35% to 45% in the 3 studied cohorts. All 3 cohorts were aggressive, initiating feeding within 0.5-1 min, and had similar feeding periods ranging from 10 to 18 min. A majority (75.3-97.9%) of the hybrids defecated when feeding, immediately after feeding, or in less than 1 min post-feeding. In contrast, only 7-42% of nymphs of T. sinaloensis defecated during the same period. Our results regarding the 6 parameters studied confirm the potential role of T. p. nahuatlae as an efficient vector of T. cruzi. Triatoma sinaloensis, on the other hand, exhibited limited vectorial capacity primarily due to its poor defecation behavior. Continued surveillance of these "sylvatic" triatomine populations is necessary to prevent an epidemiological problem.