Biology of three species of North American Triatominae (Hemiptera: Reduviidae: Triatominae) fed on rabbits

Abstract

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 biology of three Mexican-American species of Triatominae (Hemiptera: Reduviidae): Triatoma recurva, Triatoma protracta and Triatoma rubida

“…All of the species studied had average incubation periods of approximately 19 days, reflecting the favourability of the maintenance conditions for the development of these species. The egg hatching rate for T. protracta (72.5%) was similar to the rates observed for three related former subspecies of T. protracta (currently synonymised to T. protracta): Triatoma protracta navajoensis Ryckman (74.2%), Triatoma protracta nahuatlae Ryckman (76%) and Triatoma protracta zacatecensis Ryckman (81.9%), all of which were fed on rabbits (Ryckman 1962, Martínez-Ibarra et al 2007). The egg eclosion rate of T. rubida in the current study (72%) was similar to the eclosion rate (70.5%) of the former subspecies Triatoma rubida sonoriana (currently synonymised to T. rubida) found in a previous study of specimens from Caborca, a municipality that is distant from the area from which the founder specimens of our T. rubida colony were collected (Martínez-Ibarra et al 2005).…”

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Biological information is widely available for the 13 most common domestic triatomines (Hemiptera: Reduviidae: Triatominae) among the 30 species described in Mexico (Martínez-Ibarra et al 2007, Salazar-Schettino et al 2010). Information about the remaining species is scarce, primarily because these species have rarely been collected and are difficult to raise under laboratory conditions.

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“…Studies on the behaviour of triatomine species provide a greater understanding of the habits of these insects and therefore facilitate improved decision-making regarding the priorities for vector control. To our knowledge, there has been no study of the biological parameters (life cycle and feeding and defecation behaviours) of T. recurva; in contrast, two recent studies were devoted to the examination of certain behaviours of T. protracta (Martínez-Ibarra et al 2007, Klotz et al 2009) and three studies focused on T. rubida (Martínez-Ibarra et al 2005, Klotz et al 2009, Reisenman et al 2011. Even though the biological parameters of the two latter species have been studied previously, it is necessary to determine the particular behaviours of geographically distinct populations of the same species because it is likely that differing environmental conditions result in different behaviours for distinct populations of the same triatomine species (Licón-Trillo et al 2010).…”

Trypanosoma cruzi and Chagas' Disease in the United States

“…In 1951 Wood reported the following average postfeeding defecation times (minutes) for the adults of four U.S. species: T. protracta, 30.6 (n ϭ 10); T. rubida, 1.6 (n ϭ 5); T. recurva, 75.7 (n ϭ 3); and P. hirusta, 35.0 (n ϭ 2) (327). In a similar study in 2007 using both nymphs and adults of three Mexican species (also present in the United States), Martinez-Ibarra et al reported the following results: T. protracta, 6.7 (n ϭ 475); T. lecticularia, 8.3 (n ϭ 368); and T. gerstaeckeri, 11.5 (n ϭ 733) (183 (153). In that study, it was noted that none of the bugs of either species defecated on the host during the experiment.…”

Life cycle of Triatoma ryckmani (Hemiptera: Reduviidae) in the laboratory, feeding patterns in nature and experimental infection with Trypanosoma cruzi

“…If we calculate the same rate in other species of triatomines (sum of developmental periods of 4th and 5th instar nymphs/sum of developmental periods of 1st, 2nd and 3rd instar nymphs) we find that this is not the case for them. (Zeledón et al 1970, Galvão et al 1995, Martínez-Ibarra et al 1999, 2003, 2007, Cabello & Lizano 2001, Rocha et al 2001, Emmanuelle-Machado et al 2002, Wolf et al 2004, LuitgardsMoura et al 2005, Villacis et al 2008). …”