453 resultados para molt


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The external infestation of Callinectes ornatus Ordway, 1863 and Callinectes danae Smith, 1869, in particular cirripeds, was studied for two consecutive years in the Ubatuba Bay (SP) (23 degrees 26' S and 45 degrees 02' W). Bryozoans, polychaetes and cirripeds were found on both swimming crab species, but cirripeds were the most abundant and frequent. The number of infested swimming crabs increased proportionally to carapace size, but not surpassing 30 %, suggesting an absence of terminal anecdysis in both species. The establishment of the pernicious organisms on their hosts is influenced by other factors, such as their habit of burying themselves in sediments. The correlation between molting activity in adult specimens of both sexes and the low incidence of epizoonts suggest that C. ornatus and C. danae may be molting after maturity.

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Arenaeus cribrarius is a mainly tropical crab that occurs in the Western Atlantic Ocean, Brazil being its type-locality. The species ranges from Vinevard Sound, Massachusetts, USA to La Paloma, Uruguay. Information about this species is scarce. The relative growth of A. cribrarius was analyzed, based on some morphometric relations, where the carapace width, excluding lateral spines (CW), was used as an independent variable. A total of 403 specimens (189 males and 214 females), was collected in Ubatuba, State of São Paulo, Brazil, with otter-trawls. The animals were sexed and sorted to maturation phase (juvenile or adult). Some measurements were made: carapace (length and width excluding lateral spines), abdomen (greatest width of the fifth somite in females and the sixth in males) and major chela (greatest length, width and height, dactylus length). This study was made by the application of the power function (y=a.x(b)) which was fitted to the data and the pattern of growth established for each parameter by the ''b''-value (constant of allometry), as positive allometry (b>1), negative allometry (b<1) or isometry (b=1). The morphometric relations of the carapace showed a tendency to isometry. In females, the abdominal width grew in positive allometry, higher in juveniles (b=1.33) than in adults (b=1.18). In this case, an overlap and discontinuity was noticed between the phases over a carapace width range of 55 to 70 mm, where the puberty molt occurs. The majority of relationships showed that the major chela of the males grew in positive allometry, however, the greatest allometric difference between the phases was observed towards the propodus length with 1.09 as juvenile and 1.26 as adult ''b''values. In the males, this variable showed an inflection between the CW range of 45' to 55 mm, where the transition to the maturation phase occurs. The relative growth of this species is similar to those of previously studied species. This indicates, that the propodus length and the abdominal width are the morphometric variables most appropriate to estimate the size of the beginning of the sexual maturity for males and females of this species, respectively.

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The biometric relationship between the weigth and the carapace width in the swimming crab A. cribrarius was compared with the results from other portunid crabs studied previously. During November/1988 to October/1989, a total of 403 specimens (189 males and 214 females) were collected with otter-trawl nets in north coast of the São Paulo State, Brazil. The animals were measured (carapace width excluding lateral spines = LC! and weighed (wet weight = PE). The empiric points of this relation were fit according to the power function (Y = a.X(b)) for each sex, maturation phases and total of individuals. The relation PE x LC indicates that the mole's growth changes during the ontogenesys from isometric (in juvenile phase) to allometric positive (in adult phase). For the females the growth is isometric in the two phases. The weight grows in a higher proportion than the carapace width variable (allometric positive growth). The data can be grouped in a single equation (PE = 7.85.10(-5).LC(3.14)) for the convertion between the variables there was a greater similarity between the equations obtained far each sex. In spite of this, the males present the fattening grade value (''a'') slightly higher than that of the females, possibly because of the greater size reached in its devellopment. The mean weight of the males is greater than the females one (p < 0.01). In the range 80 proves 90mm the males were more abundant, probably due to the females terminal ecdysis is near this size. The females only have the mean weight greater than the males in the 60 proves 70mm range (p < 0.01) when the puberty molt occurs and they present morphological changes in their reproductive system.

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

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The lacewings (Ceraeochrysa cincta) are important predators found associated to many pests in several agroecosystems. Eggs of Sitotroga cerealella and Anagasta kuehniella are used traditionally for massal rearing of these predators. Other foods can be used in substitution to the traditional ones, but little is known about the biology of lacewings and other alternative foods. So, this work was carried out to evaluate the effect of different diets on the post-embryonic development of C. cincta in laboratory. After been individualized in glass tubes, each larva was fed with S. cereallella and Diatraea saccharallis. It was evaluated the larvae duration, weight and viability in each instar, the duration, weight and viability of the pupa and pre-pupa stages and the duration of the post-embryonic period. It was adopted a completely randomized design with ten replications per treatment, each consisting of five eggs or larvae of C. cincta. Larvae were weighed 48 hours after hatching and 48 hours after each molt, and pre-pupae and pupae, 48 hours after starting these stages. There was no effect of the kind of food provided on the parameters evaluated. Therefore, D. saccharallis eggs can be used to feed C. cincta.

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To investigate the reproductive biology of Callinectes ornatus gonadal and moulting cycles were studied over two consecutive years in the Ubatuba region. Six stages of gonadal development were detected in females and four in males. Observations on the number of ovigerous females, on the moulting stages of males and females, and on the percentage of individuals exhibiting mature gonads reveal a continuous reproductive cycle, the stages of which progress at different rates. These data support the hypothesis that C. ornatus shows staggered spawning, with possibly more than one annual reproductive period. A pause in growth before the terminal moult may occur in this species.

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Although Amblyomma brasiliense Aragão 1908 has been reported as one of the most aggressive ticks to humans in Brazil, information about the biology of this tick species is virtually inexistent. This work reports data on the life cycle of A. brasiliense fed on rabbits and pigs and maintained in an incubator at 20°C, 90% RH and 12 h of light for off-host development. Tick yield of adult females fed on pigs and rabbits was 81.2% and 58.3%, respectively. Females fed on pigs had mean engorgement weight of 862.3 mg and egg mass of 208 mg, while females fed on rabbits had mean engorgement weight of 606.1 mg and egg mass of 160 mg; these values did not differ statistically between host species. Feeding period of female ticks fed on pigs (10 days) was significantly shorter than that on rabbits (17 days). Mean preoviposition period was slightly longer (35.9 days) for ticks fed on pigs than on rabbits (30 days). The minimum incubation period of eggs of ticks from both host species was similar and over 100 days. Egg production efficiency was low for females fed on both hosts (less than 30% and 20% for ticks from pigs and rabbits, respectively). More than 55% of larvae and 79% of nymphs fed on rabbits, set free inside the feeding chambers, engorged successfully. These ticks attained an engorgement weight of 1.3 and 18.2 mg, respectively, and fed for approximately 5 days. The minimum pre-molt period was 30 days for engorged larvae and over 44 days for nymphs. Molting success was low, less than 50% in the case of larvae and less than 20% for nymphs. Further studies are required to better determine the off-host requirements of this tick species. © 2008 Springer Science+Business Media B.V.

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Deformities and abnormalities in crustaceans have been associated to genetic problem, which occurred during molt process, damage caused by ectobionts, predators or environmental stress caused by chemical wastes. Some crab specimens collected in the São Paulo littoral were found having body abnormalities. They belong to the following crab species: Callinectes ornatus (Ordway, 1863), Arenaeus cribrarius (Lamarck, 1818) and Leurocyclus tuberculosus (H. Milne Edwards; Lucas, 1843). Samplings were performed by trawling during July 2008, August and October 2009 at the Ubatuba region, São Paulo State, Brazil. Body abnormalities were verified in the cheliped dactyl (C. ornatus an adult male), carapace deformities (A. cribrarius an adult male) and abdominal alterations (C. ornatus an adult female; L. tuberculosus an adult male and an ovigerous female). The record and analysis of such occurrences can help in the distinction of natural or human impact caused alterations. In this way, the occurrence study of this kind of body alterations could provide tools in order to control unprotected environmental areas, as well as bring subsides to understand the unusual variations during the ontogeny of important species in the benthic community.

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The functions of the fat body in the different castes of termites, and accumulation of energy reserves, proteins and urates within this organ, are reviewed. The termite fat body is involved in multiple metabolic activities, including recycling of nitrogen. Termite fat body showed three different types of cells: adipocytes, urocytes and mycetocytes, the latter restricted to the species Mastotermes darwiniensis. Adipocytes synthesize and store lipids, glycogen and several proteins. These cells also elaborate important peptides, including some that act in immune processes. Urocytes are responsible for the storage of spherocrystals of urates, which vary quantitatively among the termite castes. The different metabolic functions of the fat body in the several castes and stages of termites are associated with specific adipocyte morphologies. The synthesis and storage of different compounds modify the structure of the fat body; this differentiation is coordinated by hormones involved with molting and reproductive cycles. © 2013 Elsevier Ltd.

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Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei. © 2013 Sociedade Brasileira de Zoologia All rights reserved.

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This study provides histochemical data of the hepatopancreatic cells of adult female pink-shrimp (Farfantepenaeus brasiliensis) at two different developmental stages (those with developed gonads and those with exhausted gonads). The F. brasiliensis females were collected in seawater off the Guarapari coast, Espirito Santo, Brazil. Five cell types were identified in this digestive gland: B (vesicular), E (embryonic), F (fibrillar), M (basal) and R (resorptive). The digestive gland was stained with the following techniques: PAS/Alcian blue (for polysaccharides), bromophenol blue (for protein), von Kossa (for bound calcium) and Baker (for lipids). Acid glycoconjugates were found inside vacuoles in the R cells, while neutral polysaccharides were present in the B cells and near to the microvilli. In females with exhausted gonads polysaccharides were also seen in the intertubular spaces and inside the lumina of the tubules. The F and M cells were the most marked by the presence of large amounts of proteins observed in R cells and also inside the vacuoles of B cells. The bound calcium was mainly found in the F and M cells. The F cells showed strong positive staining for lipid while the R cell only stained weakly. The E cells did not react to any of the applied staining techniques. The similarities in the histochemical composition of these hepatopancreatic cells in females with developed gonads, compared to exhausted ones, is justified by the fact that transfer of these elements to the oocytes occurs, in significant quantity, only during the initial stages of gonadal development in F. brasiliensis. Also, they may be more related to the molt stage, as in the case of calcium salts. © 2013 Elsevier GmbH. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The relative growths of Persephona lichtensteinii, P. mediterranea, and P. punctata were investigated on the south-eastern Brazilian coast, focusing on differences in the growth rates between immature and mature phases, the onset of morphological sexual maturity, and the breeding seasons of these species. Crabs were collected every two months from January 1991 through to November 1992, from a shrimp fishing boat equipped with two otter-trawl nets. Significant differences in the patterns of body growth were observed between immature and mature phases of all three species. Changes in the growth rates of the chelipeds (males) and abdomen (females) observed for P. lichtensteinii, P. mediterranea, and P. punctata, seem to be related to the puberty moult for both sexes. Males of P. mediterranea and P. punctata reached larger mean sizes of carapace width than females, whereas no difference was recorded for P. lichtensteinii. The body size at which 50% of males attained sexual maturity was also larger in P. mediterranea and P. punctata, and smaller in P. lichtensteinii. The absence of a pronounced sexual dimorphism and the size at the onset of sexual maturity observed only for P. lichtensteinii might be explained by distinct reproductive strategies of males. The presence of ovigerous females during the entire sampling period suggests that all three species have a continuous reproduction pattern at the Ubatuba region. Future studies on the population structure, functional maturity, and mating system should improve the understanding of factors driving the biology and ecology of these species at a subtropical region. © Marine Biological Association of the United Kingdom 2013.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)