Showing papers by "Gustavo Ferreira Martins published in 2013"

The Fine Structure of the Spermatheca in Anopheles aquasalis (Diptera: Culicidae)

Abstract: The vectorial capacity of mosquitoes is related to the reproductive output, and dependent on the ability of male spermatozoa to survive within the inseminated female. Mosquito females mate once, and immediately after mating, the male spermatozoa are transferred to and maintained in the ectodermic spermatheca. Mosquito spermathecae in culicines, especially of the yellowfever mosquito Aedes (Stegomyia) aegypti (L.), have been characterized in detail. In contrast, not much is known about this organ in anophelines. Here, the morphology of the spermatheca in the saltwater-tolerant mosquito Anopheles aquasalis Curry was investigated for the first time using a combination of light, confocal, and scanning and transmission electron microscopy. The spermatheca in An. aquasalis share many features with the three spermathecae present in Ae. aegypti, including a round-shaped reservoir and spermathecal duct glandular cells. However, differences such as the volume and cell types, as well as their numbers and di...

Morphological and morphometric studies of the antennal sensilla from two populations of Atta robusta (Borgmeier 1939) (Hymenoptera: Formicidae)

Abstract: The ant Atta robusta is endemic to the “restinga” ecosystems where it has an important role in the dynamics of seed dispersal. Despite its importance, A. robusta is considered a threatened species. In this study we analyzed the antennal sensory organs of two different populations of A. robusta (from the cities of Sao Mateus and Marica in in Espirito Santo and Rio de Janeiro States, respectively) using a scanning electron microscope (SEM). SEM revealed different types of sensilla in the A. robusta antennae, i.e., curved and straight trichoid, basiconic, ampullacea and coeloconic, which were highly abundant found in the distal flagellomeres (F) compared with other antenna regions. There were differences in samples collected from two locations in terms of the sensilla number and length. The average numbers of straight and curved trichoid sensillae numbers were different in F9 and F8, respectively, while the average length of the curved trichoid sensilla was only different in F9. These variations in sensory organs between two populations of A. robusta may indicate an adaptation of this species to different environmental conditions. The number of straight trichoid sensilla was only significantly different in F9.

Histochemistry and ultrastructure of urocytes in the pupae of the stingless bee Melipona quadrifasciata (Hymenoptera: Meliponini)

Abstract: The main cell types of the adult bee fat body are trophocytes and oenocytes; however, in pupae of some newly emerged bees, trophocytes are modified into cells called urocytes, which possibly function as a substitute for Malpighian tubules during metamorphosis when larval tubules are not functional and/or storage of urate salts is required. This study evaluated the morphology of urocytes in the stingless bee Melipona quadrifasciata and the possibility of maintaining these cells in primary culture. The urocytes M. quadrifasciata are white spherical cells with an irregular surface as observed by stereomicroscopy. They may be found individually or in groups associated with tracheae. Urocytes have a single, small, and spherical nucleus and cytoplasm rich in neutral polysaccharides, lipid droplets, protein, and granules containing calcium and urate salts. Our findings suggest that urocytes play a role in storage of neutral polysaccharides and calcium in M. quadrifasciata pupae and that these cells can be cultured for 72 h.

Estudo comparativo das sensilas antenais de operárias de Melipona scutellaris (Hymenoptera: Apidae) de diferentes altitudes

Abstract: Sensilas sao estruturas sensoriais presentes nas antenas dos insetos e sao responsaveis pela higro- quimio-, termo- e mecanorrecepcao. No presente trabalho, as sensilas presentes nos tres flagelomeros (F) mais distais de Melipona scutellaris Latreille (Hymenopera: Apidae) coletadas em diferentes altitudes (200 e acima de 900m) foram avaliadas qualitativamente e quantitativamente. A identificacao, contagem e medicao das sensilas foram feitas a partir de imagens da superficie dorsal das antenas que foram obtidas com o auxilio de microscopio eletronico de varredura. Foram observadas as sensilas placoide, basiconica, celoconica, ampulacea, campaniforme e tricoide reta e curvada. Comparativamente, o grupo localizado a 200m de altitude possui sensilas tricoides retas em maior quantidade nos tres flagelomeros, enquanto que o grupo de altitudes acima de 900m apresentou maior quantidade de sensilas tricoides curvadas no F9, sendo as mesmas maiores para o F10. Essas diferencas foram discutidas em funcao da localizacao geografica dos diferentes grupos aqui estudados. Os resultados da investigacao da estrutura antenal de M. scutellaris contribuem para um melhor entendimento da biologia dessa especie. A Comparative Study of the Antennal Sensilla of Melipona scutellaris Latreille (Hymenoptera: Apidae) Workers From Different Altitudes Abstract. The sensilla are sensitive structures located in different insect parts including antennae. They are responsible for the hygro- chemo-, thermo- and mechanoreception. In the present work the antennal topography of two different populations of Melipona scutellaris Latreille (Hymenopera: Apidae) from different altitudes (200 and above 900m) were studied considering the last three distal antennal flagelomers (F). Images of the antennal surface were obtained with the aid of the scanning electron microscope (SEM). The SEM analysis showed that the sensilla placodea, basiconic, coeloconic, ampullacea, campaniform and trichodea are present in the dorsal surface of the M. scutellaris antennae. The number of sensilla trichodea of the straight subtype is greater in the last three flagelomers in individuals of 200m altitude, while individuals located above 900m altitude has a greater number of sensilla trichodea of the subtype curved in the F9 and they have greater length in individuals of 900m altitude only in the F10. These differences were discussed according to the geographic location of the different groups studied here. This work represents the first assessment to antennal structure of M. scutellaris and contributes to a better understanding of the biology of this species.

The Midgut of the Parasitoid Campoletis flavicincta (Hymenoptera: Ichneumonidae)

Abstract: The midgut epithelium of insects is composed mainly of digestive cells, responsible for the di- gestion and absorption of food, and regenerative cells, which play a role in cell renewal. The morphological and histochemical analyses of the midgut of Campoletis flavicincta (Ashmead) (Hymenoptera: Ichneumonidae) showed that it is similar to those of other Hymenoptera. Mor- phometric analyses revealed differences in cell height, length of the striated border, and nuclear area of the digestive cells along the midgut. The nuclear area of regenerative cells was similar between the anterior and posterior midgut regions. These results demonstrate that the anterior and posterior midgut regions are morphologically distinct from each other.