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

The values of biological parameters related to hatching, lifespan, the number of blood meals between moults, mortality, time lapse before the beginning of feeding, feeding time and defecation delay for each instar of three Mexican-American species of Triatominae, Triatoma recurva, Triatoma protracta (former subspecies protracta) and Triatoma rubida (former subspecies uhleri), were evaluated and compared. No significant (p > 0.05) differences were recorded among the three species with respect to the average time required to hatch. This time was approximately 19 days. The average egg-to-adult development time was significantly (p < 0.05) shorter for T. rubida. The number of blood meals at each nymphal instar varied from one-five for each species. The mortality rates were higher for the first-instar nymphs of the three species studied. The mean time lapse before the beginning of feeding was between 0.3-3 min for most nymphs of all instars of each species studied. The mean feeding time was the longest for T. recurva, followed by T. protracta. The defecation delay was less than 10 min for T. recurva and T. rubida. Given these results, only T. rubida should be considered an important potential vector of Trypanosoma cruzi transmission to humans in areas of Mexico where these species exist, whereas T. recurva and T. protracta would be of secondary importance.

Presencia de Meccus longipennis y Triatoma recurva en el estado de Durango, México / Presence of Meccus longipennis and Triatoma recurva in the state of Durango, Mexico

Se reporta por primera vez la recolecta de ejemplares de Meccus longipennis (Usinger) y de Triatoma recurva (Stål) en el estado de Durango. La búsqueda de triatominos se realizó durante 12 meses (septiembre 2010-agosto 2011) en cuatro comunidades de dos municipios (Pueblo Nuevo y Mezquital) del estado de Durango. Se recolectaron 71 ejemplares de M. longipennis y seis de T. recurva provenientes mayoritariamente del interior de las viviendas humanas (recámaras). La presencia de M. longipennis en el área abre la posibilidad de un riesgo potencial de transmisión de Trypanosoma cruzi Chagas a las poblaciones humanas del área estudiada.

The collection of Meccus longipennis (Usinger) and of Triatoma recurva (Stål) in the state of Durango is reported for the first time. Both species were collected during twelve months (from September 2010 to August 2011) in four localities of two municipalities (Pueblo Nuevo y Mezquital) in the state of Durango. Seventy one specimens of M. longipennis and six of T. recurva were collected mostly from indoors of human dwellings (bedrooms). Presence of M. longipennis means a potential risk of transmission of Trypanosoma cruzi Chagas to human populations in the study area.

Biological and genetic aspects of experimental hybrids from species of the Phyllosoma complex (Hemiptera: Reduviidae: Triatominae)

The present work is a thorough investigation of the degree of reproductive isolation between Meccus mazzottii and Meccus longipennis, Meccus picturatus, Meccus pallidipennis and Meccus bassolsae, as well as between M. longipennis and M. picturatus. We examined fertility and segregation of morphological characteristics in two generations of hybrids derived from crosses between these species. The percentage of pairs with (fertile) offspring was highest in the set of crosses between M. longipennis and M. picturatus, and lowest between M. mazzottii and M. picturatus. Most first-generation (F1) individuals from crosses involving M. mazzottii were morphologically similar to this species, while only F1 x F1 progeny of parental crosses between M. mazzottii and M. longipennis had offspring second generation that looked like M. mazzottii. The results indicate that different degrees of reproductive isolation apparently exist among the species of the Phyllosoma complex examined in this study. The biological evidence obtained in this study does not support the proposal that M. longipennis and M. picturatus are full species. It could indicate on the contrary, that both could be considered as subspecies of a single polytypic species. On the other hand, biological evidence supports the proposal that M. mazzottii is a full species.