Morphological and molecular characterization of Triatominae bugs collected in Sonora, Mexico

Triatomines (Hemiptera: Reduviidae: Triatominae) are vectors of Trypanosoma cruzi, the causative agent of Chagas disease. This study aimed to assess the diversity of triatomines collected in 2023 from various regions of the State of Sonora, in Northwestern Mexico, from both wild (mainly rodent nests) and urban sites. Overall, 75 wild nests were dissected, with 36% (27/75) positive for triatomines. A total of 180 triatomine specimens were collected, including 170 collected in wild nests, and ten collected in human dwellings. Identification was performed using taxonomic keys (for adults only) as well as sequencing of a fragment of the nuclear internal transcribed spacer 2 (ITS-2) (for both adults and nymphs). Our results confirmed the presence of at least four triatomine species: Hospesneotomae sinaloensis (formerly Triatoma sinaloensis), T. rubida, Hospesneotomae protracta (formerly Triatoma protracta), and T. recurva. Notably, T. rubida and H. protracta (T. protracta), on the one hand, as well as T. rubida and H. sinaloensis (T. sinaloensis) on the other hand, were frequently found cohabiting in the same nest. Furthermore, this work provides the first ITS-2 molecular characterization of H. sinaloensis (T. sinaloensis), and its phylogenetic relationships with other members of the Triatomini tribe. Divergent haplotypes were found, that could be related to the presence of cryptic species in our study area.