Showing papers by "Gustavo Ferreira Martins published in 2008"
TL;DR: The observation of histological sections and SEM showed that the secretory cells in the venom gland of P. nigriventer form complex structures, secretory units, which originate at the base near the muscular layer and that extend into the central area until the gland lumen, contributing to the increase of thesecretory surface area and also accommodating a higher number ofsecretory cells.
16 citations
TL;DR: The fat body modifications after the blood ingestion may be associated with midgut expansion after blood feeding, followed by ovary hypertrophy that mechanically compresses the fat body against the body wall, leading to the organ’s reorganization in the body cavity.
Abstract: The fat body is the intermediary metabolism organ of insects and the main source of hemolymph components. In the current study, the microanatomy of Aedes aegypti (L., 1762) fat body was studied through scanning electron microscopy to observe the effects of blood feeding and aging. Three groups of female mosquitoes were used: newly emerged females, 18-d-old sugar-fed females, and 18-d-old blood-fed females. In Ae. aegypti, the fat body is located beneath the integument, and it is subdivided into dorsal, ventral, and lateral lobes, with the latter two being larger than the dorsal lobes. The lobes projected into the body cavity, and they were covered externally by a basal lamina with rounded cells beneath it. In 18-d-old sugar-fed females, the ventral and dorsal fat bodies seemed more developed than in newly emerged mosquitoes. The fat body hypertrophy caused by aging in the sugar-fed mosquito was probably associated with lipid accumulation due to the sugar diet. The blood-fed 18-d-old mosquitoes showed flattened fat bodies in all locations. The fat body modifications after the blood ingestion may be associated with midgut expansion after blood feeding, followed by ovary hypertrophy that mechanically compresses the fat body against the body wall. The structural changes in the fat body after a bloodmeal may be important for midgut extension to maximize blood storage and subsequent ovary enlargement, leading to the organ's reorganization in the body cavity. In addition, the depletion of fat body content during vitellogenesis could be responsible for the shrinking and flattening of the fat body lobes.
11 citations
01 Jan 2008
TL;DR: The present work provided the first description of the spermatheca morphology in the reproductive females of P. erythrocephalus that can be used as a basis for future specific studies about reproduction, caste or behaviour characteristics of Polistinae.
Abstract: The morphology of the Polistes erythrocephalus (Latreille) (Hymenoptera Vespidae Polistinae) spermatheca was studied through scanning and transmission electron microscopy. The spermatheca of P. erythrocephalus was located closely above the vagina. It consists of a spherical reservoir, a paired elongated gland and a duct connecting the reservoir to the vagina. The duct and reservoir consist of a single epithelial layer. This layer is formed by columnar cells rich in mitochondria. In addition, we observed several basal cell membrane infoldings associated with mitochondria in the reservoir epithelium. These characteristics stressed the possible role of the component cells in exchange processes between hemolymp and spermatheca lumen. The duct and the reservoir epithelia are surrounded by a further epithelial tissue: the spermatheca sheath. This is a layer of spindle-like cells that may contribute to spermatozoa isolation and maintenance. The present work provided the first description of the spermatheca morphology in the reproductive females of P. erythrocephalus that can be used as a basis for future specific studies about reproduction, caste or behaviour characteristics of Polistinae.
7 citations