Dimorfismo sexual em Belostoma angustum lauck (insecta, heteroptera, belostomatidae) pode estar relacionado ao cuidado paternal

Abstract

Belostoma angustum comprises part of a complex of three very similar species, which present post-zygotic paternal care of the ―back-brooding‖ type and possibly the sexual system is polyandry. Belostoma has many behavioral variations associated with the performance of parental care activities in the hind legs, and sexual selection can promote sexual dimorphism in these structures. Does parental care require special structures for its maintenance? The presence of sexual dimorphism in the femoral and posterior tibial functional region length, body size, shape and size of the hemelytral was evaluated by evaluating the effect of the presence of the pilose cell at this stage and the modularity of the hemieliters. The existence of relations of dependence between body size and hind legs, and between the shape and size of the centroid of the hemelytron and hind legs, taking into account the covariance between variables was also tested, as well as the sexual dimorphism in these relations of dependency. Body measurements of 138 individuals of both sexes of B. angustum, as well as the use of morfogeometric tools and path and multigroup analyzes were used for these purposes. The results suggest that sexual dimorphisms of size, biased to males, in the intercepts referring to the maximum width of the hemelytron and interocular space, may be related to sexual selection in the maximum width of the hemelytron and differences in foraging between genders and / or salivary gland in males, respectively. Although the medial and posterior femoral margins do not show statistically significant differences between the sexes, they present isometric correlations between: femur 3 and body width and, hypoallometric between: tibia 3 and body length. It is suggested that there is a sexual dimorphism in these allometric relationships in B. angustum, supported by a balance between sexual selection and viability costs, a stabilization in egg mass size and a general preservation of the hemelytron in both sexes. Sexual dimorphism in the intercepts may be related to sexual role reversal in Belostomatinae. Thus, future experiments are necessary to understand the evolutionary processes involved in this phenomenon