Showing papers by "Clóvis Andrade Neves published in 2003"

Ultrastructural study of the metamorphosis in the midgut of Melipona quadrifasciata anthidioides (Apidae, Meliponini) worker

Abstract: The ultrastructural modification of the midgut of Melipona quadrifasciata anthidioides during metamorphosis are described. Larvae of the last instar have the midgut epithelium formed basically by the digestive cells and for the small regenerative cells that are placed in nests scattered among the digestive cells. In the prepupae, digestive cells show degenerative signs, with the presence of many autophagic vacuoles. These cells detach from basement membrane and are cast out into the midgut lumen. At the same time, regenerative cells start differentiating and give rise to the pupal digestive cells. In the pupae, nests of regenerative cells are not observed. During pupation some apoptotic cells are endocytosed for the neighboring ones. The basement membrane undergoes modifications because it is flat and regular in the larval stages, it becomes very infolded during the pupation. While in adults, it emits projections that penetrate in the basal infoldings of the digestive cells. The muscular layer that involves the midgut is observed during the whole period of the metamorphosis, but some fibers or part of them are substituted. It is probable that the cellular nests that are observed in abundance among the digestive cells are formed from the small undifferentiated basal cells that are observed only among the pupal digestive cells.

FMRFAMIDE-LIKE IMMUNOREACTIVE MIDGUT ENDOCRINE CELLS IN DIFFERENT CASTES OF THE BEE Melipona quadrifasciata anthidioides (APIDAE; MELIPONINI)

Abstract: FMRFamide-like immunoreactive cells have been identified in almost all insect species studied. However, the functions of this peptide are still unknown, although several studies have suggested that FMRFamide may play a role in controlling peristalsis, digestion, development and reproduction in insects. Differences in the number, morphology, and distribution of FMRFamide-like cells have been observed among insects. Social bees are characterized by the presence of well-defined castes, each with a different behavior, energy demand and nutrient consumption. In this work, we used immunofluorescence to assess the number, morphology, and distribution of FMRFamide-like immunoreactive cells in different castes of the bee Melipona quadrifasciata anthidioides. These immunoreactive cells were observed only in the posterior region of the midgut, whereas FMRFamide-immunoreactive nerve fibers were more abundant in the fore- and hind-midgut boundary. However, there were no differences in the number and distribution of FMRFamide-like cells among the castes. This localization of immunoreactivity may indicate that the nervous system controls the passage of food through the cardiac and pyloric valves, while the passage of food through the midgut is controlled by midgut endocrine cells. The number, morphology and distribution of midgut FMRFamide-like cells were not influenced by behavior, feeding habits, caste, or sex in this species.