Extended stage duration and diminished fecundity in deltamethrin‐resistant Triatoma infestans (Klug, 1834) of the Argentinean Chaco

MAZA, VÍCTOR A.; NATTERO, JULIETA; GASPE, M. SOL; CARDINAL, M. VICTORIA

MEDICAL AND VETERINARY ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2023

0269-283X

Pyrethroid-resistance is an emergent trait in populations of various insect species. For Triatomainfestans (Klug, 1834) (Heteroptera: Reduviidae), the major vector of Chagas disease inthe southern part of South America, hotspot areas of pyrethroid-resistance have recentlybeen found in the Chaco Province of Argentina. Resistant condition can reduce fitness ofindividuals in the absence of insecticide exposure, that is, fitness costs. We evaluated theexistence of developmental and/or reproductive costs in T. infestans collected from two areasof pyrethroid-resistance in Chaco Province, Argentina. Three toxicological groups weredefined from field-collected insects: susceptible (survival 80%). Cohorts of the three toxicologicalgroups were followed-up to study life cycle and reproductive parameters. Additionally, weparameterized matrix population growth models. First and IV nymphal stages of the resistantgroups exhibited a longer stage duration than susceptible ones. The reproductive days andhatching success showed significant lower values revealing reproductive costs for the resistantgroups. Matrix analysis showed lower population growth rates for the resistant groups.Our results support developmental and reproductive costs for pyrethroid-resistant individuals.This trait could be interpreted as lower population recovery ability for pyrethroidresistantindividuals compared to susceptible insects after alternative vector control actions.