Aspects related to hatching, lifetime, number of blood meals for molting, mortality, feeding time, and postfeeding defecation delay were evaluated and compared in each instar of three North American Triatominae:Triatoma gerstaeckeri, Triatoma lecticularia and Triatoma protracta, all of them fed on rabbits. No significant differences (p > 0.05) were found among the three species regarding mean hatching rate, which was close to 20 days. Egg-to-adult development times were significantly shorter (p < 0.05) for T. lecticularia. Number of blood meals for molting to next instar ranged from one to five for T. protracta, and from one to six for T. gerstaeckeri and T. lecticularia. Mortality rates were higher in younger nymphs of T. lecticularia and T. protracta, while rates in T. gerstaeckeri were higher in fifth-instar nymphs. Mean feeding time was longest in T. gerstaeckeri, followed by T. lecticularia. More than twice the number of T. gerstaeckeri nymphs completed the development process, if compared to the nymphs from the other two species. Defecation delay was less than 10 min for T. lecticularia, T. protracta and the youngest nymphs of T. gerstaeckeri. Results point out that these three species may be important potential vectors of Trypanosoma cruzi for human populations, in areas of Mexico where these species are currently present.Key words: North America -Triatominae -biology -laboratory conditions Chagas disease is considered an emerging illness in the United States. Although only a few chronic cases have been detected in that country, a significant number of presumed cases of American trypanosomiasis has been recorded, as well as at least twelve different species of reservoir hosts (Navin et al. 1985, Hanford et al. 2007) and a near number of triatomine species (Galvão et al. 2003). In Mexico, on the other hand, it is believed that Chagas disease represents an important problem (CruzReyes & Pickeri-López 2006), with foci in some states on the USA border (e.g., Chihuahua, Sonora and Nuevo León) (Paredes et al. 2001, Licón-Trillo 2006, MolinaGarza et al. 2006, and also other probable foci in other border states of Baja California, Coahuila and Tamaulipas. Triatoma gerstaeckeri (Stål) is one of the major species of Triatominae in states on both sides of the USAMexico border, whereas Triatoma lecticularia (Stål) and Triatoma protracta (Uhler) are regionally important on that area. However, the three species stand out due to their distribution, association with human dwellings, and entomological indexes (Zárate & Zárate 1985, Galavíz-Silva et al. 1991a, Martínez-Ibarra et al. 1992, Beard et al. 2003, Galvão et al. 2003, Molina-Garza et al. 2006, Hanford et al. 2007. Studies on the behavior of triatomine species help to widen knowledge about their habits, what results in improving awareness with regard to decisions for vector control. Several studies have been devoted to specific aspects of behavior in T. gerstaeckeri and T. lecticularia (Pippin 1970, Jurberg & Costa 1989, Galavíz-Silva et al. 1991b, Torres-Estrada ...

The objective of this study was to determine some of the most important bionomic parameters related to the capacity of transmission of Trypanosoma cruzi and to estimate the potential transmission capacity and role of 3 groups of recent colonized Mexican Triatoma barberi, T. rubida sonoriana, and Meccus (formerly Triatoma) mazzottii in the prevalence of Chagas disease cases based on the distribution area of each species. Among the studied Triatominae species, the life cycle was shorter in T. r. sonoriana and longer in T. barberi, by as much as 4 times. The 1st and 5th instars had the highest rates of mortality in most of the studied species. Statistically significant shorter duration of feeding of instars was observed for T. r. sonoriana and longer duration was found for M. mazzottii when the species were compared. The mean number of blood meals per nymphal stadium was statistically greater in T. barberi than in T. r. sonoriana and M. mazzottii. Triatoma r. sonoriana and M. mazzotti had shorter defecation delay than in T. barberi and the delay was uniform in all instars. Most of the studied parameters showed that T. r. sonoriana and M. mazzotti could have an important potential role in the prevalence of Chagas disease cases where these species are commonly found.

Several biological parameters related to the