Repositório RCAAP

During the reproductive season Blue-black grassquit (Volatinia jacarina) males are found in clusters, wherein they exhibit a distinctive display that consists of repeated, vertical leaps while simultaneously producing a brief vocalization. The main objective of this study was to describe details of the species' reproductive behavior in a "Cerrado" area of central Brazil and compare these data with some studies carried out in other areas. The data obtained concerning different aspects of nesting, laying and hatching were generally similar to those obtained in previous studies in other areas. However, we found that the typical clutch size of two eggs per nest is lower, and egg and nestling mortality rates higher in our area than what has been reported elsewhere. Our results suggest that males differ in time expended with different activities according to their reproductive condition and also provide extensive parental care. We found that display execution rates peak in the early morning and in the late afternoon and are higher in the middle of the breeding season. We also found that there is an inverse relation between the height of the display leap and the height of the perch.

Fish reproductions were studied in two river basins (Corumbataí and Jacaré-Pepira basins) in the State of São Paulo, southeastern Brazil. In the Corumbataí basin, four sites were sampled: Cabeça River, Lapa Stream, Passa-Cinco River, and Corumbataí River; in the Jacaré-Pepira basin, three sites were sampled: Tamanduá Stream, Jacaré-Pepira River, and Água Branca Stream. A total of 12 bimonthly samples were made. Fish equipment included gill nets, purse seines, sieves, and traps. The main objective of this study was to characterize the fish assemblage regarding their reproductive biology and to compare these reproductive traits between both river basins. Most individuals with gonads in stage C (mature) and in stage D (empty gonads) were captured in the spring and summer. Multiple spawn and parental care were common strategies, which guaranteed offspring survivorship in unstable conditions.

Growth parameters were estimated for Moenkhausia dichroura (Kner, 1858) (Characiformes, Characidae), a small-sized and very abundant fish of the Pantanal lentic habitats commonly known as "pequira ". A method based on the length frequencies distribution and the ELEFAN I routine from the FISAT program were used. The fish were collected in the Baia da Onça, an oxbowlake of the sub-region Pantanal of Aquidauana, Mato Grosso do Sul, Brazil, from June to December 1988. The standard length of the captured fishes ranged from 29 to 76 mm with an average of 53 mm. The estimated growth parameters were L<FONT FACE=Symbol>¥</FONT> = 81 mm (standard length), k = 0.85 year-1, C = 0.89, WP = 0.6 (Rn = 0.285). The WP indicated that growth reduction occurred in July, when the lowest temperature of the year was registered. The growth curve showed that captured individuals belonged to three cohorts. The obtained results seem robust and quite compatible with the biology of the fish and its adjustment to the environment. M. dichroura, in spite of not being a direct fishing interest, is an important species in terms of its ecological aspects, due to its abundance and high growth rate, and as a great food source for aquatic organisms and specially for larger fish of economic value. Considering the information gap about small fish, the parameters estimated for pequira constitute a comparison base for other growth studies of small-sized fish species of tropical environments.

The objective of this study was to analyse the phenological events in the herbaceous and subshrub layer in relation to rainfall and the dispersion syndromes of the species at a Campo Sujo community in the Água Limpa Farm (FAL), Brasília-DF. Campo Sujo is a grassland Savannah with a few scattered shrubs and small trees. The climate is Aw by Köppen classification with a mean annual precipitation of 1500 mm. Herbaceus species with three to ten individuals were monitored totalling 519 individuals of 61 species. The individuals were observed quarterly from October 1999 to February 2001. An accidental fire happened in the area two months before the beginning of this study and stimulated flowering and fruiting of the studied species. Flowering at the community level was distributed all over the study period with a concentration of flowering species in the rainy season. The pattern of fruiting was similar to the flowering, with most species maturing their diaspore from the middle to the end of the rainy season. The correlation between anemochoric species producing mature fruits and precipitation was significant and inverse. Anemochoric and autochoric species are dominant at the herbaceous-subshrub layer of the Campo Sujo and they determine the phenological pattern of the community.

The larval morphology of Hypsiboas leptolineatus was studied. The tadpole has an ovoid body in lateral view, wider than deep; snout rounded with dorsal reniform nostrils; spiracle sinistral with lateral wall attached to body; anal tube dextral; tail fins convex with acuminate tip; oral disc ventral; labial tooth row formula is 2(2)/3(1); moderately developed beaks with serrated jaw sheaths. These external oral features are compared with those of the known tadpoles in the Hypsiboas polytaenius clade. The oral cavity was studied using an electron microscope. Life history aspects are commented.

Eriocnema fulva Naudin is a perennial herb, endemic to Minas Gerais state, SE Brazil, found on humid, shaded rocky riverbanks in montane semideciduous seasonal forests. The species is threatened, but information regarding its biology is still lacking, although such information is fundamental to any management plan. We aimed to evaluate the reproductive system of Eriocnema fulva in the Jambreiro Forest (19° 58'-59' S and 43° 55'-52' W, 800-1100 m altitude), municipality of Nova Lima, by experiments carried out in 1997 and 1998. The flowers are white, and flowering is of the steady state type, occurring once a year from November to December. Anthers are poricidal, and pollen is the only resource for visitors. The chromosome number is n = 17 during meiosis. The species is self-compatible, but does not produce fruits by spontaneous self-pollination or agamospermy; it requires pollen vectors and buzz pollination in order to produce fruits. Cross-pollination is the main reproductive strategy of E. fulva, and is accentuated by the small number of flowers (one or two in each plant) opened per day. Although the population studied was shaded by forest canopy, the seeds needed light to germinate. Germination ratio was lower in germination cabinet on filter paper (14% after 30 days) than in greenhouse on soil brought from the forest (47% after 25 days). Although the fruit is a capsule and the seeds are small, dispersion (anemochory or hydrochory) does not seem to occur at long distance, as it is the case for other Melastomataceae species with similar syndrome.

Eight species of Brachyura and two species of Anomura were registered for the first time on the Santa Catarina coast, in the waters around the Arvoredo Marine Biological Reserve. The animals were collected by scuba divers, between 3 and 22 meters depth, from September 2001 to February 2003. A total of 31 decapod species were collected, and most of the new occurrences had already been registered in the adjacent northern waters.

We studied the defensive strike of one species of each of five recognized lineages within the genus Bothrops, namely, B. alternatus, B. jararaca, B. jararacussu, B. moojeni and B. pauloensis. The defensive strike of the studied species was in general similar to that of Crotalus viridis and C. atrox, but some important differences were observed. Bothrops alternatus and B. pauloensis struck preferentially from a tight body posture, whereas B. jararaca and B. moojeni from a loose body posture. Defensive strikes were either true or false (during the latter, the mouth remains closed or partially open). Almost all strikes were successful; only on a few occasions snakes missed their target (flawed strikes). Strike variables were very conservative among the five species, especially strike distance and height, and one possible explanation may be related to constraints imposed on strike variables as a way of increasing strike accuracy.

Cytogenetic analyses were performed in two Curimatidae species (Steindachnerina insculpta and Cyphocharax modesta) from the Paranapanema and Tietê Rivers (São Paulo State, Brazil), showing a karyotype composed of 54 meta-submetacentric chromosomes in both species. Silver- and chromomycyn-staining and fluorescent in situ hybridization (FISH) using a 18S rDNA probe indicated that the nucleolar organizer regions (NORs) of both species are localized in the terminal region of the long arm of two metacentric chromosomes. Although a single NOR system was evidenced in both analyzed species, S. insculpta and C. modesta presented the nucleolar organizer regions in distinct chromosome pairs, indicating that these cistrons can be considered cytogenetic markers. Variation on the amount and distribution of the constitutive heterochromatin (C-bands) could also be detected between the two species - while S. insculpta presented few heterochromatic blocks, intensely stained C-bands were evidenced in C. modesta specially in the terminal region of the long arm of the NOR-bearing chromosomes. Although most Curimatidae species have been characterized by homogeneous karyotypes, isolated populations could be established under different environmental conditions leading to karyotype micro-structure variations specially related to the NORs localization and C-banding distribution. The obtained data were useful for the cytogenetic characterization and differentiation of S. insculpta and C. modesta and could be used in evolutionary inferences in the Curimatidae group.

The Pacu Piaractus mesopotamicus is the most captured fish species in the Pantanal, Mato Grosso do Sul State, and since 1994, its maximum sustainable yield had already been exceeded. Its capture is carried out only by hooks, as mesh gears are forbidden either for professional or for recreational fishing. The aim of this study was to determine selectivity for different hook sizes used in P. mesopotamicus fishing and to verify which sizes capture only adults. Data were collected in the rivers Miranda, Aquidauana, and Vermelho, in January, March, and April 2002. Six longlines with eight hook sizes were used and we adopted the hook opening as a measure related to selectivity. Different hooks captured individuals of the same length and their medians were similar, evidencing the great overlap among sizes. Regression results showed no significant relationship between ln[c2 (l)/c1 (l)] and total length of captured individuals. In addition, the Kolmogorov-Smirnov test also did not detect significant differences in the size of captured fish. Several hypotheses, such as the selectivity models, shape of selection curves, scarcity of large fishes, and behavior are used in order to explain the absence of hook selectivity for this species. Size of recruitment for this gear was 28 cm of total length, when individuals are still immature.

Sex ratio is an essential component of life history to be considered in population growth. Chrysomya albiceps is a blowfly species with a naturally biased sex ratio. In this study, we evaluated the impact of changes in sex ratio on the dynamic behavior of C. albiceps using a density-dependent mathematical model that incorporated demographic parameters such as survival and fecundity. These parameters were obtained by exponential regression, with survival and fecundity being estimated experimentally as a function of larval density. Bifurcation diagram of the results indicated the evolution of stable equilibrium points as a function of sex ratio. A continually increasing sex ratio yielded a hierarchy of bifurcating stable equilibrium points that evolved into a chaotic regime. The demographic parameters obtained by exponential regression were also changed to maximum and minimum values in order to analyze their influence on dynamic behavior with sex ratio being considered as an independent variable. Bifurcations with periodicity windows between chaos regimes were also found.

Growth is one of the most important aspects in the genetic improvement of cultured fish species. Consequently, genetic parameters related to this feature and their response to selection have been the focus of most research in this area. Such research indicates that, in general, there is enough additive genetic variance related to growth, justifying the use of selection. Based on the usefulness of cytogenetic and molecular markers in the fish culture, the aim of the present work was to analyze the possible relationships among cytogenetic characteristics, specifically the NOR phenotypes, and the increase in length and weight in specimens of the rainbow trout (Oncorhynchus mykiss), resultant from directed mating between homozygous females and heterozygous males according to their NOR phenotypic patterns. The equations of the relationship between length and weight of the analyzed specimens followed the model Wt = a Lt b, showing b values higher than 3, determinant of a positive allometric growth. The results showed that the different NOR phenotypes were not related with the growth values for length and weight in any statistical test.

The research aimed to study the morphologic variation of the testis, seeking to promote the selection and genetic control of those that present appreciable spermatic production throughout the year. Testis morphology of the Rynchotus rufescens partridge was investigated, analyzing the testis weight, the seminiferous tubules diameter, the thickness of the seminiferous epithelium, the amount of meiotic figures and the thickness of the tunica albuginea. Sixty male partridges were used, divided in 12 groups, and one group per month had the testis collected for the histological routine and the sections were stained using the Hematoxilin-Eosin technique. For the histological sections analysis, morphometric measures were taken, with the aid of an Image Analyzer and the resulting data were submitted to analysis of variance and to Tukey's test. Based on the histological modifications of the seminiferous epithelium and the morphometric analysis, the partridge testis morphology could be divided in four successive phases throughout the year. The reproductive phase occurred in the spring, characterized by the complete spermatogenesis process. The regression phase occurred in the summer, with the involution of the seminiferous epithelium. The rest phase took place in the fall, with spermatogonias presence and some spermatocytes beginning the meiosis. The phase of recrudescence occurred in the winter, with the recovery of the seminiferous epithelium and absence of spermatozoa. In conclusion, the characteristics analyzed revealed a variation over the year, with greater production of spermatozoa in the spring and less in the winter.

This study aimed to demonstrate the influence of the systemic administration of l-5-hydroxy-tryptophan (L-HTP) on the plasma levels of melatonin during the dark period in quails. Throughout daylight, the plasma levels of melatonin did not differ significantly, oscillating between 110.2 ± 15.8 pg.mL-1 and 157.4 ± 34.8 pg.mL-1, from 8 to 16 hours. L-HTP (25 mg.kg-1, through the intracelomic route) administered at 18 hours lessened significantly the nocturnal increase of the plasma levels of melatonin (controls, 327.3 ± 20.1 and 315.8 ± 20.9 pg.mL-1 vs. 242.1 ± 24.8 and 217.5 ± 21 pg.mL-1, respectively, at 20 and 24 hours, P < 0.05). The results obtained showed that the administration of LHTP reduced the nocturnal melatonin release, possibly by bringing about an increase in serotonin synthesis and synaptic release in the pineal. Therefore, the serotoninergic transmission from the raphe towards the pineal would constitute a mechanism of modulation of the synthesis and melatonin release in quails.

The Pycnogonida from Uruguayan waters are scarcely known, and their reports are markedly discontinuous. In this paper, several individuals of two previously unrecorded Pycnogonids at the shallow rocky subtidal and lower intertidal fringes of Cerro Verde (Rocha, Uruguay) are reported. The specimens were assigned to Pycnogonum pamphorum Marcus, 1940 and Anoplodactylus petiolatus (Kroyer, 1844). This is the first record of these species on the Uruguayan coast and the southernmost record of P. pamphorum, previously recorded only in Santos, Brazil (type locality).

Stomach contents were examined from 102 banded puffer, Colomesus psittacus (Tetraodontidae), caught from intertidal mangrove creeks at diurnal neap tides between June and September, 1997 (early dry season) near Bragança (north Brazil). The study found that C. psittacus were specialized predators of Cirripedia (Balanus spp.) and Brachyuran crabs (Uca spp., Pachygrapsus gracilis) (mean: 58 and 38% by dry weight, respectively), emphasizing a short food chain in the mangrove system. Cirripedia and Brachyura dominated the diet in all size classes, however, the prey spectrum narrowed with fish size. The mean daily consumption of Cirripedia and Brachyura was 6.2% body weight of C. psittacus. On average C. psittacus consumed 100.3 g.ha-1.d-1 of Cirripedia and 178.7 g.ha-1.d-1 of Brachyura (wet weight). The predation on Brachyuran crabs - a significant driver of fluxes of organic matter and energy in the system - provides C. psittacus with an important ecological function in the mangrove food web. A plant-animal interaction is proposed where C. psittacus exerts a mutually beneficial cleaning function on the Aufwuchs (Cirripedia and associated epibiota) of Rhizophora mangle stilt roots. Our results and those of other studies suggest that C. psittacus encounter optimum foraging conditions in the mangrove at high inundations at daylight (spring tide-day) whereas darkness and low inundations are linked to poor foraging conditions (neap tide-night). The C. psittacus resource could be used as an alternative income in the region in terms of i) sustainable catch and filet processing for exports to East Asia, ii) developing certified aquaculture methods for breeding puffers for the aquarium trade.

The aim of this study was to evaluate the benthic diatom composition from the estuary sediment in the Pernambuco State, based on 32 samples. Samples were collected monthly from September through December 1999 (dry period) and from April through July 2000 (rainy period) during four pre established sampling stations. Results indicated 19 families and 31 specific and infraspecific taxa. Eight new records were founded for Pernambuco State: Auliscus coelatus, Fallacia nummularia, Navicula algida, Plagiograma pulchellum, Terpsinoe americana, Triceratium antideluvianna and Tryblionella coarctata and one, Auliscus punctatus Bailey, in northeastern Brazil.

Several studies suggest that, on a large scale, relief conditions influence the Atlantic Forest cover. The aim of this work was to explore these relationships on a local scale, in Caucaia do Alto, on the Ibiúna Plateau. Within an area of about 78 km², the distribution of forest cover, divided into two successional stages, was associated with relief attribute data (slope, slope orientation and altitude). The mapping of the vegetation was based on the interpretation of stereoscopic pairs of aerial photographs, from April 2000, on a scale of 1:10,000, while the relief attributes were obtained by geoprocessing from digitalized topographic maps on a scale of 1:10,000. Statistical analyses, based on qui-square tests, revealed that there was a more extensive forest cover, irrespective of the successional stage, in steeper areas (>10 degrees) located at higher altitudes (>923 m), but no influence of the slope orientation. There was no sign of direct influence of relief on the forest cover through environmental gradients that might have contributed to the forest regeneration. Likewise, there was no evidence that these results could have been influenced by the distance from roads or urban areas or with respect to permanent preservation areas. Relief seems to influence the forest cover indirectly, since agricultural land use is preferably made in flatter and lower areas. These results suggest a general distribution pattern of the forest remnants, independent of the scale of study, on which relief indirectly has a strong influence, since it determines human occupation.

Two new species of the genus Hisonotus are described from the upper Rio Tapajós basin, Mato Grosso State, Brazil. They are small species, growing up to about 30.0 mm SL, having the scapular bridge wide and totally exposed or having a small median pair of arrector fossae, and the abdomen completely covered with large plates in adult specimens (about 23.0 mm SL). They are distinguished from their congeners by the following combination of characters: Hisonotus chromodontus has 20-40 reddish-brown tipped premaxillary teeth, and 15-38 on the dentary bones; 2324 plates on the longitudinal series; a prominent large dark brown lateral stripe extending from the tip of the snout to the caudal blotch; transversal dark brown bars very inconspicuous or absent. Hisonotus luteofrenatus has a moderate number (12-28) of hyaline or slightly yellow-tipped premaxillary teeth, and 9-26 on the dentary bones; 25-26 plates on the longitudinal series; a characteristic yellow line extending from the anterior part of each orbit, over the inferior nostril, both converging to the tip of the snout.

The germinability of artificially buried Psychotria hoffmansegiana and Palicourea marcagravii seeds in Cerrado soil was tested, with the aim of evaluating whether dispersed seeds may be able to form a soil seed bank. The assays were carried out at a Cerrado Reserve in São Paulo State, Brazil. Seed samples were placed in nylon bags and buried at two different depths and in two different sites. Samples were periodically exhumed and germination tests were performed with both exhumed and dry stored seeds. In general, soil storage favoured seed survival and germination when compared to dry stored seeds. The seed germination was little affected by soil depth and by burial environment. Seeds of both species remained viable for at least 13 months, considering the time lapse between the collection and the end of the germination tests. It was suggested that both species can potentially form a persistent soil seed bank in Cerrado.