Showing papers in "Brazilian Journal of Biology in 2002"
TL;DR: The aim of the present work was to provide researchers with some helpful considerations about the determination of the rat estrous cycle phases in a fast and practical way.
Abstract: The short length of the estrous cycle of rats makes them ideal for investigation of changes occurring during the reproductive cycle. The estrous cycle lasts four days and is characterized as: proestrus, estrus, metestrus and diestrus, which may be determined according to the cell types observed in the vaginal smear. Since the collection of vaginal secretion and the use of stained material generally takes some time, the aim of the present work was to provide researchers with some helpful considerations about the determination of the rat estrous cycle phases in a fast and practical way. Vaginal secretion of thirty female rats was collected every morning during a month and unstained native material was observed using the microscope without the aid of the condenser lens. Using the 10 x objective lens, it was easier to analyze the proportion among the three cellular types, which are present in the vaginal smear. Using the 40 x objective lens, it is easier to recognize each one of these cellular types. The collection of vaginal lavage from the animals, the observation of the material, in the microscope, and the determination of the estrous cycle phase of all the thirty female rats took 15-20 minutes.
1,322 citations
TL;DR: The condition factor for nine species of tropical freshwater fish in the upper Paraná River floodplain is described and knowledge of the nine species is important for adequate management and maintenance of the biological equilibrium of the ecosystem.
Abstract: The condition factor for nine species of tropical freshwater fish of the Characidae family in the upper Parana River floodplain is described. Fish were caught over a period of 12 months (February 1993 to March 1994). Knowledge of the nine species is important for adequate management and maintenance of the biological equilibrium of the ecosystem.
205 citations
TL;DR: The species composition and abundance of the zooplankton community of seven reservoirs of the Paranapanema River, located between 22 degrees 37'-23 degrees 11'S and 48 degrees 55'-50 degrees 32'W, were analysed over four periods, in the year of 1979.
Abstract: The species composition and abundance of the zooplankton community of seven reservoirs of the Paranapanema River, located between 22o37'-23o11'S and 48o55'-50o32'W, were analysed over four periods, in the year of 1979. The zooplankton community was composed of 76 species of Rotifera, 26 species of Cladocera and 7 species of Copepoda. For a large part of the period under study the Rotifera were dominant, followed by Copepoda. The Piraju and Salto Grande reservoirs, which occupy intermediate positions in the cascade of reservoirs, were richest in species, most of them belonging to Rotifera and Cladocera. In the reservoirs Rio Pari and Rio Novo, lateral to the cascade of reservoirs, a lower species richness was observed, although higher densities of organisms were found than in the other reservoirs located in the main river body. Different rotifer species occurred in succession, being abundant in different periods, with no defined pattern. Among the copepods, Thermocyclops decipiens predominated in the majority of the reservoirs. Ceriodaphnia cornuta was the most abundant cladoceran in the intermediate reservoirs of the cascade, and Daphnia gessneri, Bosminopsis deitersi and Moina minuta, in the reservoirs lateral to the cascade. The most frequent zooplankton species were Notodiaptomus conifer, Thermocyclops decipiens, Ceriodaphnia cornuta cornuta and C. cornuta rigaudi, Daphnia gessneri, Bosmina hagmanni, Keratella cochlearis and Polyarthra vulgaris. Some relationships were found between the trophic state of the reservoirs and the zooplankton community.
183 citations
TL;DR: The changes in red blood cells suggest a compensatory response to respiratory surface reduction of gills in order to maintain oxygen transference from water to the tissues, allowing the fish to survive during the so-called shock phase of LC50 exposure, at least while at rest.
Abstract: Hematological and physiological changes in the blood of juveniles of the freshwater fish, Prochilodus scrofa were determined after acute exposure to 20, 25, and 29 mgCu L-1 in water (pH 7.5; hardness 24.5 mg L-1 as CaCO3) for 96 h. Copper exposure to 25 and 29 mgCu L-1 caused significant increase in the hematocrit and red blood cell values. The increase in red blood cells was associated with increase in whole blood hemoglobin only in fish exposed to 29 mgCu L-1. Leukocytes increased following copper exposure and were significantly higher in fish exposed to 29 mgCu L-1. Differential leukocyte percentage displayed significant reduction in lymphocytes and an increase in neutrophils in fish exposed to 25 and 29 mgCu L-1. The percentage of monocytes remained unchanged after copper exposure. The thrombocytes did not change. There was a significant decrease in plasma [Na+] and [Cl-] and a significant drop in blood pH in fish exposed to 25 and 29 mgCu L-1 while [K+] showed significant increase in fish exposed to 29 mgCu L-1. Copper exposure led to ionoregulatory impairment, although chloride cell hypertrophy was induced. The changes in red blood cells suggest a compensatory response to respiratory surface reduction of gills (tissue damage and cell proliferation) in order to maintain oxygen transference from water to the tissues, allowing the fish to survive during the so-called shock phase of LC50 exposure, at least while at rest.
176 citations
TL;DR: Two Atlantic Forests and two Cerrado areas in Brazil were sampled for non-flying small mammal fauna to suggest that species could be divided into different ecological categories according to distribution, use of altered and/or relatively unaltered vegetation and habitat specificity.
Abstract: Two Atlantic Forests and two Cerrado areas in Brazil were sampled for non-flying small mammal fauna. In each biome one area with altered and another with almost unaltered vegetation (national parks), were chosen to investigate these fauna. Species richness of Atlantic Forest and Cerrado was comparable in the conserved as well as in the altered areas. Data suggested that species could be divided into different ecological categories according to distribution, use of altered and/or relatively unaltered vegetation and habitat specificity. Within these ecological categories some species are appropriate indicators for monitoring environmental quality and degradation. Useful guidelines for wildlife management planning, including selecting areas for conservation units and their better boundary delimitation can ensue.
110 citations
TL;DR: Headwater can be classified as "trout zones" and from these zones to downstream areas fish communities changed because of the addition of other fish species, probably because of an increase in habitat diversity.
Abstract: We analyzed the variation of fish species richness and trophic structure along an upstream-downstream gradient and identified the factors associated with the pattern observed. The fish community composition varied along a headwater-downstream gradient. Species richness and trophic structure decreased significantly with increasing altitude and increased with stream order and distance from source. Headwater communities showed a simple structure. Oncorhynchus mykiss was the only fish captured or noticeably dominant at high altitudes. Thus, headwater can be classified as "trout zones". From these zones to downstream areas fish communities changed because of the addition of other fish species. This phenomenon probably occurs because of an increase in habitat diversity.
70 citations
TL;DR: Most fish species have parental care, which could explain the absence of planktonic larvae, and early life stages of fish do not exert a predation pressure on the lake zooplankton.
Abstract: For evaluating the trophic relationship between early life stages of fish and zooplankton in Lake Monte Alegre, fish distribution and feeding habits have been studied in areas with and without macrophytes. In the first of these areas, 356 specimens belonging to 8 species, mostly juveniles, were caught by a sieve. Another 35 specimens, belonging to 4 species, were caught by gill nets and seine in areas lacking macrophytes. Their diets were composed of aquatic insects, microcrustaceans, rotifers, detritus, and other aquatic invertebrates. Microcrustacean prey were mainly littoral or benthic dwellers, found in the highest proportion in specimens of 7-20 mm SL. Most fish species have parental care, which could explain the absence of planktonic larvae. Early life stages of fish do not exert a predation pressure on the lake zooplankton.
65 citations
TL;DR: A strong relationship between the variations in the chironomid community and fluctuations in limnological characteristics is suggested, and on a seasonal scale, the flood pulse seems to be the main controlling factor of the temporal variation in densities and dominance of ch ironomid larvae.
Abstract: Chironomid larvae were collected and abiotic variables measured at monthly intervals at 21 sampling stations in two lagoons (Guarana and Patos) and two tributaries (Baia and Ivinheima) of the Upper Parana River floodplain. The genera Procladius, Chironomus, Goeldichironomus, and Polypedilum were dominant in the lagoons and in the Baia River, while Cryptochironomus and Lopescladius were more dominant in the Ivinheima River. The similarity in the generic composition of the chironomids of the lagoons and the Baia River is probably due to the fact that this river presents hydrodynamic characteristics similar to those of the lagoons. The results obtained suggest that the hydrodynamics of these environments are the main factor determining spatial variation in the chironomid fauna. This is intuitively clear, as this factor itself determines sediment type, quantity of organic matter and presence or absence of aquatic macrophytes. However, on a seasonal scale, the flood pulse seems to be the main controlling factor of the temporal variation in densities and dominance of chironomid larvae. Given that this factor has a large influence on the temporal dynamics of several limnological variables, this is again a logical correlation. Our results suggest a strong relationship between the variations in the chironomid community and fluctuations in limnological characteristics.
63 citations
TL;DR: It is observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism, which was completely regulated by a dense phytoplankton community.
Abstract: The aim of this paper was to verify hydrological and hydrochemical changes in the Iquipari Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism.
59 citations
TL;DR: The hemocyte types, in addition to total and differential hemocyte counts were studied in parasitized and unparasitized Anastrepha obliqua larvae at the beginning and at the end of the third instar.
Abstract: The hemocyte types, in addition to total and differential hemocyte counts were studied in parasitized and unparasitized Anastrepha obliqua larvae at the beginning and at the end of the third instar. In both developmental phases, in parasitized and unparasitized larvae, prohemocytes, plasmatocytes, granulocytes, adipohemocytes, spherulocytes and oenocytoids cells were observed. Mitotic figures indicate prohemocytes as stem cells. Prohemocytes, plasmatocytes and granulocytes are the most numerous cells in the hemolymph of A. obliqua. Difference in the total number of hemocytes was observed between unparasitized and parasitized larvae at the end of the third instar, but not at the beginning.
56 citations
TL;DR: Seed mass is an important biological factor, affecting seed germination, seedling elongation, and growth of these species, and favoring large seeds, specially in areas of active sand accretion like coastal dunes.
Abstract: The effect of seed mass on germination and growth was tested in fresh-seeds of Blutaparon portulacoides, Panicum racemosum, and Spartina ciliata, selected at random in southern Brazilian populations. The seed mass varied within a population of the three species. Both B. portulacoides and P. racemosum showed normal frequency distribution of seed mass, while S. ciliata did not. Significant differences were observed in seed germination between large and small seeds of all species. In all species the capacity of seedling elongation was greater in seedlings of large seeds than those of small ones. Relative growth rate of seedlings of P. racemosum and S. ciliata decreased with time in all seed mass size-classes. On the other hand, the relative growth rate of B. portulacoides seedlings increased during the first 40 days. Seed mass is an important biological factor, affecting seed germination, seedling elongation, and growth of these species, and favoring large seeds, specially in areas of active sand accretion like coastal dunes.
TL;DR: The analysis of the degree of threat has shown that the dense forest habitat has a relatively stable status of conservation while the secondary forest, the mangrove and the herbaceous vegetation on rocky outcrops are categorized as vulnerable.
Abstract: The State Park of Ilha Grande is only a part (5,594 hectares) of the entire island (19,300 hectares) which is located off the south coast of Rio de Janeiro state, between the cities of Mangaratiba and Angra dos Reis. Approximately half of the Park area (47%) is covered by dense Atlantic forest. The secondary forest growth is in a process of ecological succession close to attaining maturity (43%) and the remaining part (10%) is composed of human-altered areas (1%), rocky outcrops with herbaceous vegetation (7%), mangroves and beaches (2%). The fauna is well represented but already shows signs of degradation with introduced species. The analysis of the degree of threat has shown that the dense forest habitat has a relatively stable status of conservation while the secondary forest, the mangrove and the herbaceous vegetation on rocky outcrops (and their fauna) are categorized as vulnerable. The area altered by human occupation is considered threatened. Since the coastal area where Ilha Grande is located is well known for its beautiful scenery (known as the green coast, because of the contrast between the ocean and the Atlantic forest covering the Serra do Mar mountain chain). There is a strong possibility for tourism to become the means in which to achieve economic sustainability for conservation. Contradictorily, tourism is also the major threat to local biodiversity and its landscape units. Because tourism is not organized and controlled, during high season the numbers grow above local capacity, giving rise to a proliferation of hotels, guesthouses and camping grounds. The resulting untreated open sewage, random garbage disposal and other harmful activities form the major threats to biodiversity.
TL;DR: The aims of this study were to verify the distribution of births of captive maned wolves Chrysocyon brachyurus and the causes of their deaths during the period from 1980 to 1998, based on the registry of births and deaths in the International Studbook for Maned Wolves.
Abstract: The aims of this study were to verify the distribution of births of captive maned wolves Chrysocyon brachyurus and the causes of their deaths during the period from 1980 to 1998, based on the registry of births and deaths in the International Studbook for Maned Wolves. To determine birth distribution and average litter size, 361 parturitions were analyzed for the 1989-98 period. To analyze causes of mortality, the animals were divided into four groups: 1. pups born in captivity that died prior to one year of age; 2. animals born in captivity that died at more than one year of age; 3. animals captured in the wild that died at any age; and 4. all animals that died during the 1980-98 period. In group 1, the main causes of mortality were parental incompetence (67%), infectious diseases, (9%) and digestive system disorders (5%). The average mortality rate for pups was 56%. Parental incompetence was responsible for 95% of pup deaths during the first week of life. In group 2, the main causes were euthanasia (18%) and disorders of the genitourinary (10%) and digestive systems (8%). Euthanasia was implemented due to senility, congenital disorders, degenerative diseases, and trauma. In group 3, the main causes were digestive system disorders (12%), infectious diseases (10%), and lesions or accidents (10%). The main causes of mortality of maned wolves in captivity (group 4) were parental incompetence (38%), infectious diseases (9%), and digestive system disorders (7%).
TL;DR: A new and efficient device to characterize microhabitat structure of small mammals is proposed as a standard method to describe habitat structure and can be used in any kind of forest.
Abstract: Studies quantifying habitat structure generally use several instruments. This paper aims to propose a new and efficient device to characterize microhabitat structure of small mammals. Seven measurements were taken: plant cover, litter cover, rock cover, canopy cover, and vegetative obstruction at three heights. The device is a 0.25 m2 square wooden frame (0.50 m x 0.50 m) divided in to 100 open squares by wire mesh. Average time spent to measure each trapping station was six minutes. This new device is efficient, i.e., quick, practical, simple, and reliable. It can be used in any kind of forest. We propose this method as a standard method to describe habitat structure.
TL;DR: The results suggest that environmental variables, and food and shelter availability are the main factors in determining M. microlepis and H. malabaricus distribution.
Abstract: Longitudinal distribution of Mimagoniates microlepis and Hoplias malabaricus was analyzed in a coastal stream system in Southeast Brazil. Six sites were sampled by electrofishing in seven months, from July 94 to July 95. Densities of M. microlepis, and H. malabaricus and its prey (Poecilia vivipara, Deuterodon sp. and Astyanax janeiroensis) were estimated by the Zippin method; environmental variables of: (i) kind of substratum; (ii) percentage of pools, runs, riffles, instream vegetation, and canopy were registered for each site in each sampling month. The relative importance of each biotic and abiotic variable was tested through simple correlation analyses. We verified that M. microlepis occurrence correlates with canopy; H. malabaricus is correlated with instream vegetation, pools, clay substratum, and P. vivipara densities; and P. vivipara correlates with pools and clay substratum. Our results suggest that environmental variables, and food and shelter availability are the main factors in determining M. microlepis and H. malabaricus distribution.
TL;DR: Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis populations, and is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage.
Abstract: Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae) populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae) used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Aguas Belas Experimental Station-Viamao County), one in a Myrtaceae Forest (Itapua State Park-Itapua County) and one in the Atlantic Rain Forest (Maquine Experimental Station-Maquine County). Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this character is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.
TL;DR: The invertebrate colonization during decomposition of Eichhornia azurea was observed in a lateral lake in the mouth zone of Paranapanema River into Jurumirim Reservoir in two periods of the year and the decomposition rate was higher during the rainy season than in the dry season.
Abstract: A colonizacao por invertebrados durante o processo de decomposicao de Eichhornia azurea foi examinada em duas epocas do ano na zona de desembocadura do Rio Paranapanema, na Represa de Jurumirim, em lagoa lateral. O metodo utilizado para avaliar a taxa de decomposicao bem como a colonizacao concomitante pelos invertebrados foi o uso dos litter bags em numero de 42 com tamanho 15 ´ 20 cm e 2 mm de abertura de malha. Seis litter bags (tres para determinacao da taxa de decomposicao e tres para estimativa de densidade de organismos) foram removidos por sorteio no 1o, 3o, 7o, 14o, 28o, 56o e 72o dias de incubacao. Apos cada periodo de incubacao, o material foi cuidadosamente lavado para facilitar a separacao dos detritos e invertebrados. Em seguida, o material biologico foi fixado com formol 4% e posteriormente triado e identificado sob microscopio estereoscopico. O material vegetal remanescente foi seco a 60oC e pesado. Ocorreu rapida perda de material nas primeiras 24 horas e a taxa de decomposicao de Eichhornia azurea foi maior no periodo chuvoso, em relacao a estacao seca. A maior densidade de invertebrados nos detritos de Eichhornia azurea foi observada na estacao seca no 56o dia de incubacao com aproximadamente 110 ind.g.PS¾1 quando os detritos da planta apresentavam um teor de 0,57 UDO.g.PS¾1 de polifenois. No periodo chuvoso, a maior densidade foi encontrada no 28o dia de incubacao quando o teor de polifenois era de 4,36 UDO.g.PS¾1. Observou-se que a reducao dos teores de polifenois tem efeito aparente sobre o aumento da densidade de invertebrados. A maioria das especies encontradas pertence ao grupo dos coletores, que foi dominante no periodo chuvoso (a partir do 7o dia) e seco (a partir do 14o dia).
TL;DR: The terrestrial reptile fauna of the Abrolhos Archipelago is studied and some of its ecological aspects such as diet, thermal ecology, activity, and some reproductive parameters are analyzed.
Abstract: We have studied the terrestrial reptile fauna of the Abrolhos Archipelago (a group of five islands located ca. 70 km off the southern coast of the State of Bahia, Brazil) and analyze here some of its ecological aspects such as diet, thermal ecology, activity, and some reproductive parameters. Three lizards comprise the archipelago's terrestrial reptile fauna: Tropidurus torquatus (Tropiduridae), Mabuya agilis (Scincidae), and Hemidactylus mabouia (Gekkonidae). The first two are diurnal and the latter is crepuscular/nocturnal (initiating activity at ca. 17:30). The activity period of T. torquatus extended from 5:30 to 18:30 h. Mean field body temperatures of active T. torquatus, M. agilis, and H. mabouia were, respectively, 34.0 +/- 3.7 degrees C (range 23.8-38.0 degrees C; N = 75), 34.5 +/- 2.2 degrees C (range 30.8-37.0 degrees C; N = 6), and 26.3 +/- 1.1 degrees C (range 24.8-28.0 degrees C; N = 8). The predominant prey items in the diet of T. torquatus were ants, coleopterans, and hemipterans. In the diet of M. agilis, coleopterans were the most frequent prey items. For H. mabouia, the most important dietary items were orthopterans. Clutch size of T. torquatus averaged 4.1 +/- 1.1 (range 2-6; N = 15) and was significantly related to female size (R2 = 0.618; p = 0.001; N = 15). Clutch size for H. mabouia was fixed (two) and mean litter size of the viviparous M. agilis was 3.3 +/- 0.6 (range 3-4; N = 3). Tropidurus torquatus and H. mabouia deposit their eggs under rocks in the study area, with the former burying them but not the latter; in both species, more than one female often oviposit under the same rock.
TL;DR: A road/city-effect zone of 12 to 15 km width is suggested over which habitat loss and fragmentation extend throughout the caatinga vegetation, over which remaining vegetation was reduced by one third near cities and roads.
Abstract: Roads and cities represent huge sources of degradation for adjacent ecosystems regarding nutrient cycling, energy, water flow and species composition. In this study we test the hypothesis that distance from roads and cities is associated with habitat loss and fragmentation in the caatinga vegetation--a dry forest to scrub vegetation that covers ca. 736,000 km2 of northeast Brazil. The study site comprised a 2,828.8 km2 piece (64 km x 44.2 km) of Xingo region (09 degrees 36'S, 37 degrees 50'W), which is located between the States of Alagoas and Sergipe. Based on satellite imagery we mapped the remaining vegetation, 145 km of paved roads and the seven small-sized cities set in the study site. A positive correlation was found between the combined distance from roads and cities and the percentage of remaining vegetation as it dropped from 18% at 12 km distant to 5.9% at 1 km distant from cities and roads. Thus, remaining vegetation was reduced by one third near cities and roads. A positive correlation was also found between distance from cities and roads and the percentage of fragments larger than 200 ha, which ranged from 3.6% (within 3 km distance class) to 23.3% (15 km distance class) of all fragments. Our results suggest a road/city-effect zone of 12 to 15 km width, over which habitat loss and fragmentation extend throughout the caatinga vegetation. These findings should be considered in the regional polices for biodiversity conservation and economic development of the caatinga region.
TL;DR: Collection in open, riverside, and wetland areas, as well as the use of bait, should substantially increase the number of species in Uberlândia region.
Abstract: A total of 251 butterfly species were recorded in Uberlândia region, with collecting concentrated mainly in forest areas. Aspects of geographic distribution of some Ithomiinae, as well as interactions of both adults and immatures with plants, and reproduction periods for the more abundant species are discussed. Collections in open, riverside, and wetland areas, as well as the use of bait, should substantially increase the number of species.
TL;DR: The hourly activity data showed that the euglossine bees were attracted to the baits all day long, but at a higher frequency in the morning period, peaking between 8:00 and 10:00 h.
Abstract: A study was conducted in an early second-growth forest aiming at knowing the richness, relative abundance, seasonal distribution, and hourly frequency of euglossine bees, and their association with scent baits. Male bees were attracted to cineole, vanillin, methyl salicylate, and eugenol. The baits were hooked 1.5 m high and 6 m from one another. The specimens were collected from December 1997 to November 1998, once a month, from 7:00 to 17:00 h. A total of 339 male euglossine bees were caughts, accounting for 19 species and four genera. The most common species was E. cordata, making up 69.9% of the individuals, followed by E. truncata (2.3%), E. violaceifrons, and E. smaragdina (2.1%). The most attractive scent was cineole, which baited 87% of the specimens and 73.7% of the species. Vanillin, the second most visited bait, eured 7.6% of the specimens and 26.3% of the species. E. surinamensis was only collected with this bait. Methyl salicylate and eugenol baited combined 2.6% of the specimens. However, by species numbers Methyl salicylate attracted 21% whereas eugenol was attractive for 15.8% of them. In general, the species were more abundantly found in the rainy season (January-June). The hourly activity data showed that the euglossine bees were attracted to the baits all day long, but at a higher frequency in the morning period, peaking between 8:00 and 10:00 h.
TL;DR: The results evidenced the importance of the littoral zone as propitious habitats for the species of Chydoridae and contributing significantly to the diversity of Cladocera as a whole.
Abstract: The diversity of species of Cladocera, Chydoridae in the water bodies belonging to the water management unity of Serra da Mantiqueira, was studied inside the BIOTA/FAPESP Program. A total of 21 water bodies were analyzed and the sampling was carried out between 9th and 11th September, 1999. Horizontal and vertical net hauls were taken at littoral and limnetic region in each lake. Most water bodies in Serra da Mantiqueira unity are small, shallow, and densely colonized by macrophytes. Most species of Cladocera found belong to the Chydoridae family, being typical inhabitants of the littoral zone, living associated with macrophytes. A total of 12 species were found, 9 of the subfamily Aloninae and 3 Chydorinae. In more than half of the water bodies the relative abundance of chydorids reached 100%, and they were dominant in most of the others, with few exceptions. Alona rustica was the most frequent species, occurring in 62% of the water bodies. The results evidenced the importance of the littoral zone as propitious habitats for the species of Chydoridae and contributing significantly to the diversity of Cladocera as a whole.
TL;DR: The potential of the groundwater analyzed is evident as a source of microorganisms to be utilized in studies related to environmental remediation and the metabolic potential associated with the microorganisms of the environment studied.
Abstract: A selection of exopolysaccharide (EPS)--producing bacterial strains was conducted in groundwater adjacent to an old controlled landfill in the City of Sao Carlos (Sao Paulo, Brazil). The strains were isolated in P and E media under aerobic and microacrophilic conditions at 25 degrees C. A total of 26 strains were isolated and based on the mucoid mode of the colonies, 6 were selected and their morphological, physiological and biochemical aspects were characterized. All strains presented pigmentation, ranging from yellow to orange and from pink to salmon, with a shiny glistening aspect in all tested media. Strains Lb, Lc and Lg, which excelled the others with regard to the mucoid mode of the colonies, were selected to be cultured in E medium with alternate sucrose and glucose as carbon sources in anaerobiosis at 25 degrees C to analyze the production of EPS. Strains Lc and Lg were classified as being of order Actinomycelates, suborder Corynebacterineae. Lg strain was identified as Gordonia polyisoprenivorans and Lc strain did not correspond to a known description and therefore a more detailed study is under preparation. Considering all ecological aspects and the metabolic potential associated with the microorganisms of the environment studied, as well as the capacity to produce pigment and EPS, and the presence of G. polyisoprenivorans, a rubber degrader bacterium, the potential of the groundwater analyzed is evident as a source of microorganisms to be utilized in studies related to environmental remediation.
TL;DR: This is the first report showing that Dictyota cervicornis produces a chemical defense against herbivores using secodolastane diterpenoid, and these results widen the action spectrum of secondary metabolites found in seaweed belonging to this brown algal genus.
Abstract: Seaweed preference by the Brazilian endemic gastropod Astraea latispina was examined in the laboratory to evaluate the role of secondary metabolites in determining food choice. Of three species of seaweeds examined, Plocamium brasiliense was highly preferred; less so were Sargassum furcatum and Dictyota cervicornis were preferred less. Extracts and/or pure major metabolites of the two potentially chemically-defended seaweeds (P. brasiliense and D. cervicornis) were tested as feeding deterrents against A. latispina. Algal extract assays demonstrated that three concentrations of crude organic extract of the red alga P. brasiliense (50%, 100%: natural concentration, and 200% of dry weight: dw) did not affect feeding of this gastropod. In contrast, the three concentrations of crude organic extract of the brown alga D. cervicornis (50%, 100% and 200% dw) inhibited feeding by A. latispina. The chemical deterrent property of D. cervicornis extract against the gastropod A. latispina occurred due to a mixture of the secodolastane diterpenes isolinearol/linearol (4:1 ‐ 0.08% dry weight). This is the first report showing that Dictyota cervicornis produces a chemical defense against herbivores using secodolastane diterpenoid. In addition, these results widen the action spectrum of secondary metabolites found in seaweed belonging to this brown algal genus.
TL;DR: The crude organic extracts of the endemic gorgonian Phyllogorgia dilatata and two sponge species Aplysina fulva and Mycale microsigmatosa were evaluated for anti-fouling properties through field experiments and can provide a basis for future development of one kind of natural antifoulant technology to prevent marine bioFouling.
Abstract: The crude organic extracts of the endemic gorgonian Phyllogorgia dilatata and two sponge species Aplysina fulva and Mycale microsigmatosa were evaluated for anti-fouling properties through field experiments. To investigate this property in ecologically meaningful conditions, crude extracts from these invertebrates were incorporated at concentrations naturally found in these marine organisms into a stable gel used as a substratum for fouling settlement. Crude extract from A. fulva showed no significant anti-fouling property at the natural concentrations used in the field experiments. In fact, fouling organisms settled significantly more on gels treated with A. fulva extract than on the control gel. On the other hand, both M. microsigmatosa and P. dilatata yielded crude extracts that exhibited a selective action inhibiting only the settlement of barnacles. The evidences obtained here by means of field experiments can provide a basis for future development of one kind of natural antifoulant technology to prevent marine biofouling.
TL;DR: Twenty-seven species of calyptrate muscoids were collected from December 1993 to November 1994 with wind oriented traps baited with decomposing beef liver at the Rio de Janeiro Zoo.
Abstract: Twenty-seven species of calyptrate muscoids (Muscidae and Sarcophagidae) were collected from December 1993 to November 1994 with wind oriented traps (W.O.T.) baited with decomposing beef liver at the Rio de Janeiro Zoo. The most abundant species found were Musca domestica (57.84%), Peckia chrysostoma (28.16%), Ophyra aenescens (17.11%), Oxysarcodexia thornax (17.82%), Synthesiomyia nudiseta (13.05%), and Oxysarcodexia diana (14.52%).
TL;DR: Anatomic features observed in the three studied species such as: midrib with complex vascular system, mesophyll consisting of tabular lobed chlorophyllous elements and fusoid cells, vascular bundles with double sheath correspond to the "bambusoid type" of leaf anatomy.
Abstract: Fully developed leaves of Cryptochloa capillata (Swallen) Soderstrom, Raddia brasilienses Bertol and Pharus lappulaceus Aublet (Poaceae: Bambusoideae) were collected at Restinga de Jacarepia, Environment Proctection Area of Massambaba, county of Rio de Janeiro, State of Rio de Janeiro, Brazil, and studied by optical microscope. Leaf anatomy is described in order to contribute to the Poaceae family study. Anatomic features observed in the three studied species such as: midrib with complex vascular system, mesophyll consisting of tabular lobed chlorophyllous elements and fusoid cells, vascular bundles with double sheath, epidermis made up of long cells, short cells, micro-hairs, prickles and silica bodies correspond to the "bambusoid type" of leaf anatomy.
TL;DR: The present results show that in the ovarioles of a newly emerged (0 day) queen of A. mellifera only two regions may be distinguished: a proximal, short germarium and a very long distal, terminal filament.
Abstract: The present results show that in the ovarioles of a newly emerged (0 day) queen of A. mellifera only two regions may be distinguished: a proximal, short germarium and a very long distal, terminal filament. As the queen matures and gets ready for the nupcial flight, the germarium increases in lenght, advancing towered the distal end, as the terminal filament shortens. The ovarioles of queens ready to mate (6 to 8 days old) have, already one or two ovarian follicles, i.e. a very short proximal vitellarium, but a real vitellogenesis only starts after the fecundation. If the queen does not mate the ovarioles structure is disrupted (12-16 days old). In mated queen eggs the ovarioles present three differentiated regions, from the apice to the basis: a short terminal filament, a medium size germarium, and a very long basal vitellarium. As the eggs are laid, the emptied follicle collapses, degenerates and produces a corpus luteum.
TL;DR: Diversity and biomass of Chironomidae larvae were studied between January-November 1993 and March-November 1994 in an impacted lagoon in Rio de Janeiro, Southeastern Brazil in an attempt to establish the ecological consequences of anthropogenic eutrophication processes.
Abstract: Diversity and biomass of Chironomidae larvae were studied between January-November 1993 and March-November 1994 in an impacted lagoon in Rio de Janeiro, Southeastern Brazil, in an attempt to establish the ecological consequences of anthropogenic eutrophication processes. Nine hundred and seventy-five organisms belonging to the Tanypodinae, Orthocladiinae, and Chironominae were collected. Polypedilum (62%) and Chironomus (58%) were the most common genera found in the limnetic and littoral zones.
TL;DR: Spatial and temporal variation of climatic and physical characteristics in a shallow tropical reservoir in the city of São Paulo, Southeastern Brazil, and their possible influence on the dynamics of the phytoplankton population are studied.
Abstract: Spatial and temporal variation of climatic and physical characteristics in a shallow tropical reservoir in the city of Sao Paulo, Southeastern Brazil, and their possible influence on the dynamics of the phytoplankton population. Samples were taken at 5 depths of the water column (subsurface: 1% Io, 10% Io, 2 m, and bottom) and at 4 hour intervals (6:00, 10:00, 14:00, 18:00, 22:00, 2:00, and 6:00 h) during summer (March 3-4), fall (June 13-14), winter (August 29-30), and spring (November 29-30) of 1994 at a single sampling station. Garcas Reservoir (23 degrees 39'S, 46 degrees 37'W) is a kinetic turbulent system, highly influenced by winds, with stratification that may last for days or weeks, and which undergoes mixing periods more than once in a year. A thermal pattern of this type is comparable to the warm discontinuous polymetric. Considering its optical properties, the water body was classified as an ecosystem with moderate turbidity, which decreases basically due to increased phacopigment concentration during the spring. Also, the reservoir is an ecosystem whose phytoplanktonic community is subjected to stress, the degree of which depends on level of light penetration.