Insect Fluctuating Asymmetry: An Example in Bolivian Peridomestic Populations of <i>Triatoma infestans</i> (Klug, 1834) (Hemiptera: Reduviidae)

Abstract

Fluctuating asymmetry (FA) is a morphometric tool used to measure developmental instability in organisms which have been exposed to stress or other adverse conditions. Phenotypic variability in response to stressors are the result of interactions between genomes and the environment, acting in a noisy developmental system. Most of the organisms have bilateral symmetry with a repetition of structures in different positions or orientations; asymmetrical variation has been a morphological response associated with insecticide application inducing disturbances in endocrinal system product of the chemicals. Triatoma infestans (is the main vector of Chagas disease in South America. The availability of food sources varies for populations of T. infestans living in different habitats; insects that inhabit the intradomicile feed preferentially on human blood, whereas insects that develop in the peridomicile feed on the blood of the other mammals and birds. The following research evaluate the FA to the different ecotopes in two geographical areas of Chuquisaca Bolivia; Yamparáez/Sotomayor of the high inter-Andean valleys and Huacaya/Imbochi of the boreal Chaco and a CIPEIN laboratory strain population. A combination of advanced morphometrics tools and multivariate analysis were used to quantify the levels of asymmetry produced by pyretroid near to the peridomiciles in Bolivia. Populations from Yamparáez/Sotomayor were found to have higher levels of FA which the combination of environmental conditions such as low temperatures avoid greater permanence in the habitat and more exposition to insecticide. A better understanding of the combination of these tools will allow researchers to implement better public policies to regulate insecticide applications and to understand how certain organisms adapt to multiple stressors.

Keywords

• fluctuating asymmetry
• pesticides
• geometric morphometrics
• vector
• developmental instability