Ontogenetic shifts in the digestive tube and diet of Bryconamericus stramineus Eigenmann, 1908 (Osteichthyes, Characidae)

Aim: Studies on feeding of early life stages are very important to the understanding of the biology and trophic ecology of fish species. Therefore, the aim of this work is to describe the development of the digestive tube, and to characterize the diet of larvae and juveniles of Bryconamericus stramineus Eigenmann, 1908 of the upper Parana River floodplain; Methods: Larvae were obtained from, monthly samples during nychthemeral cycles with four-hour interval between samplings from February/91 to February/92, utilizing a conical-cylindrical plankton net; Results: At the preflexion stage, larvae at approximately 4.00 mm SL, showed a morphologically undifferentiated straight tube, with the anterior region more dilated. At the flexion stage a differentiation in the anterior region of the digestive tube occurs, with the intestine wall getting thicker (8.30 mm SL). The formation of pyloric caeca occurs at 9.00 mm SL. At the postflexion stage the first loop is formed at 9.25 mm SL and the second loop at about 10.00 mm SL. Bryconamericus stramineus consumed mainly cladocerans, also ingesting copepods, rotifers, nematodes, algae, insects and inorganic particles. Along the development, there was an increase in the number of food items and a diversification in the number of consumed taxa; Conclusions: Changes in the diet of B. stramineus larvae were not observed, being them zooplanktivores during all the initial development. However, an increase of large preys, such as insects larvae, was observed at the end of the larval period and in juveniles, suggesting a tendency towards invertivory. Larvae and juveniles preferentially fed during the night.

Post-embrionic development of the digestive tube of Dermatobia hominis (Linnaeus) (Diptera, Cuterebridae)

The digestive tube of 2nd and 3rd instar larvae, pupae and newly emerged adults of Dermatobia hominis (Linnaeus, 1781) was studied anatomically. The specimens were dissected in buffer saline under a stereomicroscope, and the digestive tubes were placed on slides and fixed in 10% buffered formalin. Each tube was measured using a micrometric eye piece, and drawings were made with camera lucida. The results showed that the midgut, the hindgut and the Malpighian tubules with their ducts grow gradually during the larval development. The oesophagus and the salivary glands with their ducts grow only during the moult from the 2nd to the 3rd instar. In the pupal period, salivary glands grow gradually but disappeared after the 20th day. After metamorphosis the digestive tube regressed. This is expected since adult D. hominis lives about nine days without feeding. This fly, similar to other calyptratae muscoid flies shows no vestige of a crop during all post-embrionic development, and the adult has no salivary glands.

Morphology of the digestive tube of Macuxitermes triceratops and its phylogenetic implications (Isoptera: Termitidae: Nasutitermitinae)

The gross morphology of digestive tube of Macuxitermes triceratops is described and illustrated. The gut of this species is very similar to those of Embiratermes and Ibitermes, and does not show any obvious autopomorphic character. The phylogenetic relations of this genus are discussed based on the available evidence, and it is concluded that it is probably the sister group of Armitermes + Curvitermes + Cryilliotermes.

Morphological characteristics of the Pterodoras granulosus digestive tube (Valenciennes, 1821) (Osteichthyes, Doradidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ultramorphology of digestive tract of Anticarsia gemmatalis (Hubner, 1818) (Lepidoptera : Noctuidae) at final larval development

The digestive tract of insects is an important natural, physical, and chemical defense barrier against pathogen invasion. Certain. lepidopteran caterpillars are serious pests of agricultural crops and their biology has received much attention, but little is known about the larval noctuid gut. The morphological analysis of the digestive tract in Anticarsia gemmatalis under scanning electron microscopy (SEM) is a good model for studies about its defense mechanism. The material was fixed (2,5% glutaraldehyde solution; 0.1 M-phosphate buffer, pH 7.3), post-fixed (1% osmium tetroxide in the same buffer), dried at critical point, gold coated and analyzed in a SEM 515-Philips. A. gemmatalis digestive tract consists of a straight duct of varying length and diameter, subdivided in three main regions: the foregut formed by the oral cavity, pharynx, esophagus, and crop; the midgut that is the largest portion of the digestive tract without noticeable morphological differentiation along its length; and the hindgut that is morphologically differentiated in pylorus, ileum, colon, and rectum. Although the general morphology of the A. gemmatalis digestive tract is quite similar to the other Lepidoptera species, the anatomical array of the crop muscular layers is quite different comparing with the description for other larval insect.

Size-related shifts in dietary composition of Centropomus parallelus (Perciformes: Centropomidae) in an estuarine ecosystem of the southeastern coast of Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise histológica do trato gastrintestinal de avestruzes jovens (Struthio camelus Linnaeus, 1758)

The histological aspects of the gastrointestinal tract of the ostrich (Struthio camelus) have been little studied, so this research is focused on such analysis. To this end, samples were obtained from different segments of the digestive tubes of five young ostriches aged 20 to 30 days. Based on the results, the authors conclude that the different segments of the digestive tube of the young ostrich presents the same general structure as that of other domestic birds and mammals, with some differences that may be due to age, the species involved, or feeding habits. It is hopes that this analysis will contribute to a better understanding of the physiological processes related to the nutrition and management of ostriches during their growth.

Morphological study of the hindgut in larvae of Anticarsia gemmatalis Hübner(Lepidoptera: Noctuidae)

A lagarta da soja (Anticarsia gemmatalis Hübner) tem grande interesse econômico, pois afeta significativamente a cultura da soja em todo o mundo. Este trabalho descreve a morfologia do intestino posterior de larvas de A. gemmatalis, com ênfase nos seus aspectos histológicos. O intestino posterior é constituído por regiões morfologicamente distintas, identificadas como piloro, íleo, cólon e reto. Independente da região, a parede do intestino posterior é constituída por fina cutícula, epitélio simples e camada muscular. A íntima cuticular apresenta espículas no anel intersticial posterior, entre o intestino médio e o posterior, e na região posterior do piloro. A musculatura do reto é formada por camada única de largas fibras circulares, diferindo das demais regiões do intestino posterior que apresentam duas camadas de fibras musculares. As extremidades distais dos túbulos de Malpighi atravessam as paredes do reto, constituindo o sistema criptonefridial característico de Lepidoptera.

Morfologia do tubo digestivo nos cupins Heterotermes tenuis (Hagen) e Coptotermes havilandi Holmgren (Isoptera, Rhinotermitidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acute and subchronic exposure of diplopods to substrate containing sewage mud: Tissular responses of the midgut

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histopathology and Ultrastructure Features of the Midgut of Adult Females of the Tick Amblyomma cajennense Fabricius, 1787 (Acari: Ixodidae) in Various Feeding Stages and Submitted to Three Infestations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

THAUMATOMYRMEX STRIPS MILLIPEDES FOR PREY - A NOVEL PREDATORY BEHAVIOR IN ANTS, AND THE 1ST CASE OF SYMPATRY IN THE GENUS (HYMENOPTERA, FORMICIDAE)

We describe, for the first time, the predatory behaviour of Thaumatomyrmex ants on millipedes of the family Polyxenidae, based on field observations of T. atrox and a field and laboratory study of T. contumax. The capture of the prey and the removal process of its body-covering setae by the ants before they eat the millipede are described. This specialized behaviour in at least two species of the genus, belonging to two distinct groups of species, indicates a general trend in Thaumatomyrmex. We coupled this study with a comparative morphological analysis of the mouthparts and digestive tube of these and other Thaumatomyrmex species. Also, we report the first case of sympatry in the genus, which suggests that Thaumatomyrmex includes several species. and not only one highly variable taxon, as hypothesized earlier.

Morfologia e enzimologia do sistema digestório dos girinos da rã-touro (Rana catesbeiana) durante o desenvolvimento e metamorfose

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aperfeiçoamento em equipamento para digestão de amostras por via úmida

Aperfeiçoamento em equipamento para digestão de amostras por via úmida. É descrito um aperfeiçoamento em equipamento para digestão de amostras por via úmida que emprega tubos de digestão (20) fechados não encapsulados e aquecimento condutivo que possibilita a rápida decomposição de amostras botânicas, alimentícias, clínicas, ambientais e similares, promovendo um gradiente de temperatura em direção à parte superior do tubo de digestão, permitindo que a temperatura da fase gasosa seja inferior à da fase líquida, de forma que as digestões são realizadas à pressão pouco elevada e, consequentemente, os tubos de digestão utilizados podem ter paredes menos espessas, permitindo o rápido aquecimento e resfriamento das amostras, bem como baixo custo de operação e manutenção, simplicidade, alta frequência analítica,; redução do consumo de reagentes e diminuição da geração de resíduos, dito equipamento provido de um gabinete (10) que evita a contaminação da atmosfera do laboratório por vapores ácidos e a perda dos componentes voláteis da amostra durante o aquecimento