Deltamethrin resistance in Triatoma infestans: phenotypic changes in head and antennae wings and their adaptive implications.

HERNÁNDEZ M.L; DUJARDIN, J.P; VILLACÍS, A.G; YUMISEVA, C.A; REMÓN C; MOUGABURE-CUETO, G

Encuentro; MexPopGen 6; 2023

UNAM

In vector control terms, insecticide resistance is the development of the capacity, to tolerate doses of an insecticide that are lethal to most individuals in a typical population of the same species. The genetic changes that determine resistance may have adaptive costs in the resistant phenotype or, conversely, may result in an adaptive advantage when compared to susceptible insects in the environment without insecticides. Triatoma infestans is one of the main vectors of Trypanosoma cruzi (Chagas disease) in the southern cone of South America. High insecticide resistance in T. infestans was detected in Argentina. The objective of this study was to determine the possible morphometric changes in wings, heads and in the antennal phenotype of deltamethrin-resistant T. infestans (RR) males and females compared to susceptible insects (SS), evaluating its implication in adaptive processes. Geometric morphometry of wings, antennae and antennal sensilla quantification were used on 106 adults of both sexes. Morphological divergence was observed between the two groups (RR and SS). The RR insects showed smaller sizes of wings and heads, and shapes compatible with lower dispersal potential and different active dispersal behaviors. Antennae also revealed sensory simplification in RR and divergence between RR and SS, although more marked in females. This study characterizes T. infestans RR and SS through wings, heads and antennae for the first time. The results suggest a lower dispersive potential in resistant insects and the differences described lay the foundations for the identification of a resistance biomarker in triatomines.