Environmental and Dispersal-Related Drivers of Color Morph Distribution in Triatoma infestans (Klug, 1834) (Hemiptera, Reduviidae)

Abstract

Understanding the dispersal capacity of Triatoma infestans, the main vector of Chagasdisease in South America, is vital for vector control and managing recolonization afterinsecticide use. This study compares the seasonal frequency of melanic and non-melanicT. infestans morphs in Northwestern Córdoba Province, Argentina, and examines theirassociation with environmental variables, morphometric traits, nutritional status, and flight capacity. Insects were collected at the beginning and end of the warm season. Dorsalcoloration, morphometric traits, nutritional status, flight-related indices, climatic variables,and vegetation cover were recorded. Chromatic morph frequencies were analyzed usingchi-square tests. Biological predictors were identified through multi-model inference, andenvironmental associations explored with Canonical Correspondence Analysis. Melanicindividuals decreased from early to late warm season, especially males. Wing loadingcorrelated strongly with morphotype, being higher in non-melanic forms. Pronotum sizewere also a significant predictor. Nutritional status had no clear effect. Cattle pasturecover and rainfall influenced morph frequency, mainly in males. These results reveal acomplex interaction between phenotypic and environmental factors shaping color morphvariation, highlighting the importance of understanding these dynamics to optimize vectorsurveillance and control in areas prone to reinfestation.