Avaliação histomorfométrica do aparelho reprodutor feminino de Tropidacris collaris (Stoll,1813) (Orthoptera : Romaleidae) submetido a três fotoperíodos

Abstract

In Brazil, the presence and the increase of the population of grasshoppers are linked, certainly, to the deforestation and to the new types of manipulation of agroforestry cultures, implanted in the cerrado and other regions. Among the species of grasshoppers of economic importance, the Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae) is highlighted. Several morphological and histological studies of the female reproductive system of the insects have been reported as an important tool for phylogenetic relationship between the insect species. Thus, the present research had the objective of proceeding the morphometry of the ovary, quantifying the ovarioles, describing the histology of the female reproductive system, besides analyzing the ultrastructure of the ovarioles of the T. Collaris that were submitted to photoperiods of 10L:14D, 12L:12D and 14L:10D, in the last instar. The morphometric averages of the ovary and the quantification of the ovarioles were submitted to the Variance analysis. Thecollected organs were fixated in alcoholic Boüin, included in “paraplast”, dyed and analyzed under light microscopy. For the transmission and analysis of the electronic light microscopy, the ovarioles were fixated in Karnovsky. The results showed two stages of development of the pre-reproductive and the reproductive ovaries. There weren’t meaningful statistical differences for the morphometry related to length and width (side-lateral and dorsoventral) of the ovaries as well as the number of ovarioles, which were of 195.62, 202.62 and 208.25 for the photoperiods 10L:14E, 12L:12E and 14L:10E, respectively. The photoperiods also have not affected the histology of the organs and the ultrastructure of the ovarioles. Each of the ovarioles presented tubular morphology and three well characterized areas. The terminal fiber is constituted by connective tissue. In the germary, the ovogonias are in intense myotic activity and associated to the follicular cells. Each section of the vitelarium is internally covered by follicular cells, containing several ovocytes in different development stages. The lateral oviduct is covered bysimple cubic epithelial tissue with numerous folds, connective and muscular tissue. In the common oviduct the epithelium presents tunica intima and a well developed muscular layer. The spermatic duct is covered by columnar pseudo-stratified epithelial tissue with a thick tunica intima and two layers of muscular tissue, one longitudinal and the other circular, and between them, connective tissue. Ultrastructurally the ovarioles presented themselves as covered by a thick sheath, constituted by a homogenous and fibrous material. In the terminal filament, it has been observed cells with voluminous nuclei and scarce cytoplasm, besides an abundant extra cellular matrix with several filamentous structures. In the germary the ovogonias are bigger with voluminous nuclei, scarce cytoplasm and cellular membrane with interdigitation. The follicularcells are smaller, presenting cytoplasmatic projections. In the vitelarium, the follicular cellssuffer modifications in their morphology, varying from cubic to flat.