Sex-specific effects of Trypanosoma cruzi infection on mating behavior in Triatoma infestans (Hemiptera: Reduviidae).

Chagas disease caused by Trypanosoma cruzi and transmitted by triatomine bugs, is a major public health concern in Latin America. Triatoma infestans, the main domestic vector in the Southern Cone, exhibits physiological responses to infection, but its reproductive behavior under chronic infection has not been characterized in detail. In this study, we evaluated the effect of T. cruzi infection on the copulatory behavior of T. infestans. Virgin males and females were paired according to infection status: both uninfected (UU), both infected (II), or mixed combinations (UI and IU). Behavioral interactions were video-recorded under controlled laboratory conditions. Our results show that copulation success was significantly reduced when females were infected, (II pairs: 33.3%, and 84.6% in UU). Mixed pairs involving infected males (UI) showed the highest number of precopulatory and postcopulatory mounting attempts. Infected males displayed increased mounting behavior and three times more al copulation attempts than uninfected males, without differences in copulation duration. These findings suggest alterations in the copulatory sequence without a reduction in overall mating persistence. Infected females exhibited more rejection responses and shorter postcopulatory associations, leading to decreased mate guarding and shorter overall mating events. These findings demonstrate that infection is associated with sex-specific alterations in mating behavior in T. infestans, with distinct patterns depending on the sex of the infected individual. This behavioral interference may reduce reproductive efficiency and contribute to changes in vector population dynamics, ultimately influencing the transmission potential of Chagas disease in endemic areas.