Head shape variation in response to diet in Triatoma williami (Hemiptera, Reduviidae: Triatominae), a possible Chagas disease vector of legal Amazônia

Triatoma williami is naturally infected by Trypanosoma cruzi, the ethiological agent of Chagas disease, the most significant cause of morbidity and mortality in South and Central America. There is a lack of data demonstrating the bionomic aspects, the vectorial competence or the natural ecotope and the wild hosts of T. williami, although this species may be considered secondary vector because it maintains their wild condition and shows synanthropic potential, colonizing the peridomiciles and frequently invading the household. The synanthropy represents a secondary adaptation by sylvatic species in response to environmental changes, and this adaptability to human dwellings depends on the plasticity of triatomine. This study describes for the first time the shape plasticity of T. williami in response to diet (blood). Two groups of triatomines were exposed to a sole blood meal source, mammalian and bird, to assess the effect of blood meal source on head morphology. The variation was analyzed using geometric morphometric tools and showed that T. williami has higher morphological variation in shape associated with blood source. This results represent an important representation of the shape adaptation of T. williami and a contribution to the knowledge of morphometrics variation of insect vector of diseases.