Fil: Iglesias, Mónica Sandra. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Valverde, Alejandra Del Carmen. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Gaspe, María Sol. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Crespo, Francisco Antonio. ANLIS Dr.C.G.Malbrán. Centro Nacional de Diagnóstico e Investigación en Endemo-epidemias; Argentina.Sexual size dimorphism (SSD) is detected in Belostoma elegans for the first time in a multivariate framework. Females are usually bigger than males in Heteroptera species; size is frequently associated with reproductive success. Following this general trend we found that maximum width of the head and interocular distance are biased towards females. Components of body size involved in paternal care and mating behavior did not follow that general rule. Therefore, SSD is not detected in total length without head and maximum width, presumably a consequence of the male egg-laying area which offers a proportional major surface for the clutch. SSD biased to males is found in middle and hind leg segments, used during mating and brooding behavior.