Vertical climbing of triatomines on building materials: Implications for house infestation risk and vector control.

Vertical climbing performance is a critical but often overlooked factor in the household colonization process by triatomine vectors. This study evaluated the climbing efficiency of seven Mexican triatomine species (Triatoma longipennis, T. mazzottii, T. pallidipennis, T. rubida, T. picturata, Paratriatoma lecticularia, and Hospesneotomae protracta) across four common regional building materials: unplastered brick, plastered brick, wood, and mesh screen. A fifth material, plastered brick with oil-based paint, was also tested. Ascent times to a height of 25 cm were recorded under scotophase conditions. Results showed that oil-based paint acted as an absolute physical barrier, with a 100% failure rate across all species. For the remaining materials, a general linear model (R2 = 0.891) revealed highly significant interactions between species and substrates (p < 0.001). Although masonry surfaces significantly hindered the movement of H. protracta, these species exhibited high efficiency on wood and mesh screen. Conversely, T. longipennis was highly efficient on brick but slower on organic substrates. In almost all cases, mesh screen allowed for the fastest ascent times, suggesting it may facilitate rapid movement if compromised. These findings demonstrate that triatomine climbing ability is species-specific and highly dependent on surface micro-rugosity. We conclude that housing improvement strategies, specifically the use of smooth, non-porous wall coatings, are essential components of integrated vector management. Such interventions, combined with modern surveillance tools, can significantly reduce the risk of domestic infestation and Chagas disease transmission in endemic regions of Mexico.