Morfologia de ovos, glândulas salivares e sistemas digestivo e reprodutor de Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)

• Autor(a) principal: Souza, Gabriely Köerich
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3961
• topic: Morfologia de ovos; Glândulas salivares; Sistemas digestivo e reprodutor; Morphology of eggs; Salivar glands; Digestive and reproductive systems; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA

The bronze bug Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae) is a pest of Corymbia and Eucalyptus species and there are no effective strategies for its control in commercial plantations. Biological data of insects of the family Thaumastocoridae are scarce, mainly with species of the subfamily Xylastodorinae. Morphological studies of eggs and digestive and reproductive systems can provide important information to control T. peregrinus. This study described the morphology of eggs, salivary glands, alimentary canal and reproductive systems of males and females T. peregrinus. Thirty females and fifteen males of T. peregrinus with different ages were obtained from a mass rearing facility in a room with temperature at 25 ± 2ºC, 70 ± 10% RH and 12 h photophase and prepared for analysis in a light microscopy. Eggs of T. peregrinus were obtained from the mass rearing facility, coated with gold and analyzed in a scanning electron microscope. Thaumastocoris peregrinus has a pair of bilobed principal salivary glands located between the segments of the meso- and metathorax. The wall of the lobes is formed by a single layer of cubic cells with some of them binucleate. Each gland has a main duct formed by a single layer of flattened cells. The alimentary canal of T. peregrinus has a short faringe followed by a long and thin esophagus that ends in a simple proventriculus and a short estomodeal valve. The midgut of T. peregrinus comprises an anterior dilated region without gastric cecae, a long and narrow middle region and a short and dilated posterior one. The hindgut is composed by a transition region with the midgut where the insertion of two pairs of Malpighian tubules occurs, a short ileum and a rectum with a folded epithelial wall, thick cuticle and flattened cells. The male reproductive system of T. peregrinus is formed by a pair of testa with three large and globular follicles isolated by a peritoneal sheath and two pairs of tubular mesadenian accessory glands well developed. The female reproductive system of T. peregrinus is formed by a pair of ovaries with two meroistic telotrophic ovarioles each. The ovarioles open into two long lateral oviducts that join into a short common oviduct. The common oviduct ends in a large bursa copulatrix with many folds and both are lined by a thick cuticle. Eggs with embryos at the stages of anatrepsis, katatrepsis and also after the dorsal closure were observed in the reproductive tract of T. Peregrinus females. Eggs of T. peregrinus are oval-shaped and flattened dorso-ventrally with a strong depression in the center and black colored. The chorion of the egg is divided into exochorion, endochorion, air layer and an inner chorionic layer. The outer surface of the exochorion lacks perforations or pores and showed shallow and elongated depressions that were more circular in the posterior region of the egg. The opercular opening is located laterally in the eggs of T. peregrinus with the neck region showing around 27 circular and concave projections that appear to be aeromicropyles, reduced chorionic rim and a narrow sealing bar internally. The operculum is elliptical and flattened and has the same texture as the rest of the corium, except for the smooth texture of the outer opercular region. Thaumastocoris peregrinus has digestive and reproductive systems similar to other species of Thaumastocoridae, but the external characteristics of the eggs of this species differ from others of the same family. Studies of a larger number of species can contribute to the knowledge and importance of the structures evaluated for identifications at the level of subfamily, genus or species and to understand the phylogenetic relationships of Thaumastocoridae.