Repositório RCAAP

Herein we present new occurrences of sites of Dendropsophus minusculus in Brazil adding information about reproductive biology and colour patterns of the species. Such information is fundamental for characterising the species that we believe has been neglected due to its morphological similarity with other congeneric species. Dendropsophus minusculus may be found in different morphoclimatic domains, being one of the most generalist species of the genus in this aspect. The species plasticity is not restricted to its occurrence, but also related to aspects of its reproductive biology, and we hypothesised that the latter feature could explain the wide geographical range of the species. We highlight the importance of further in-depth studies and the use of D. minusculus as a model to understand the historical events responsible for the current geographical distribution of the morphoclimatic domains in Brazil.

This work provides information about the sexual commitment and the folliculogenesis of the gatuzo, Mustelus schmitti. A total of 112 females of all maturity stages were fished in the Bahía Blanca estuary, between 2009 and 2010. The oogonia were present throughout the life cycle of the animals. The folliculogenesis follows a pattern similar to other elasmobranchs. The granulosa layer keeps monolayered throughout the folliculogenesis, but with two cell types in the vitellogenic follicle. The zona pellucida forms in the primordial follicles. The thecal system shows a connective inner layer and a glandular outer sheath. The microscopic beginning of the sexual commitment, indicated by the vitello hoarding, takes place in follicles from 500 micrometres, while the macroscopic evidence appears in follicles of 2500-3000 micrometres. The results presented in this study suggest that the fishery pressure may affect a susceptible range of sizes of the species, not previously considered and provides a biological framework for the development of fisheries policy.

The infection of Scomberomorus brasiliensis by the myxozoan Kudoa sp. is reported. The parasites formed plasmodiae inside the skeletal muscle fibres. The spores were quadrate in apical view and bell-like shaped in lateral view, containing four equally sized more or less rounded polar capsules. No detrimental effects were observed in the host, namely muscle liquefaction. The importance of these parasites is discussed.

Freshwater mussel species are in global decline. Anthropogenic changes of river channels and the decrease of autochthonous fish population, the natural hosts of mussels larval stages (glochidia), are the main causes. Therefore, the conservation of mussel species depends not only on habitat conservation, but also on the availability of the fish host. In Portugal, information concerning most of the mussel species is remarkably scarce. One of the most known species, Unio pictorum is also in decline however, in the basins of the rivers Tua and Sabor (Northeast of Portugal), there is some indication of relatively large populations. The aforementioned rivers can be extremely important for this species conservation not only in Portugal, but also in the remaining Iberian Peninsula. Thus, it is important to obtain data concerning Unio pictorum bioecology (distribution, habitat requirements, population structure, genetic variability, reproductive cycle and recruitment rates), as well as the genetic variability and structure of the population. Concomitantly, information concerning fish population structure, the importance of the different fish species as “glochidia” hosts and their appropriate density to allow effective mussel recruitment, will also be assessed. The achieved data is crucial to obtain information to develop effective management measures in order to promote the conservation of this bivalve species, the conservation of autochthonous fish populations, and consequently the integrity of the river habitats.

Parent-offspring vocal communication, such as the isolation call, is one of the essential adaptations in mammals that adjust parental responsiveness. Thus, our aim was to test the hypothesis that the function of the capybara infants' whistle is to attract conspecifics. We designed a playback experiment to investigate the reaction of 20 adult capybaras (seven males and 13 females) to pups' whistle calls – recorded from unrelated offspring – or to bird song, as control. The adult capybaras promptly responded to playback of unrelated pup whistles, while ignoring the bird vocalisation. The adult capybaras took, on average, 2.6 ± 2.5 seconds (s) to show a response to the whistles, with no differences between males and females. However, females look longer (17.0 ± 12.9 s) than males (3.0 ± 7.2 s) toward the sound source when playing the pups' whistle playback. The females also tended to approach the playback source, while males showed just a momentary interruption of ongoing behaviour (feeding). Our results suggest that capybara pups' whistles function as the isolation call in this species, but gender influences the intensity of the response.

A general analysis of the behaviour of “Cebus” shows that when this primate moves position to feed or perform another activity, it presents different ways of locomotion. This information shows that the brachial biceps muscle of this animal is frequently used in their locomotion activities, but it should also be remembered that this muscle is also used for other development activities like hiding, searching for objects, searching out in the woods, and digging in the soil. Considering the above, it was decided to research the histoenzimologic characteristics of the brachial biceps muscle to observe whether it is better adpted to postural or phasic function. To that end, samples were taken from the superficial and deep regions, the inserts proximal (medial and lateral) and distal brachial biceps six capuchin monkeys male and adult, which were subjected to the reactions of m-ATPase, NADH-Tr. Based on the results of these reactions fibres were classified as in Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) and Slow Twitc (SO). In general, the results, considering the muscle as a whole, show a trend of frequency FOG> FG> SO. The data on the frequency were studied on three superficial regions FOG=FG>SO; the deep regions of the inserts proximal FOG=FG=SO and inserting the distal FOG>FG=SO. In conclusion, the biceps brachii of the capuchin monkey is well adapted for both postural and phasic activities.

The orchid-bee fauna of the region of Porto Velho, in the state of Rondônia, Brazil, close to the southernmost limits of the Amazon Basin, was surveyed for the first time using five different scents as baits to attract orchid-bee males. Five hundred and twenty-one males belonging to five genera and 29 species were collected with bait traps during 26 non-consecutive days from November, 2011 to January, 2012. Eulaema nigrita Lepeletier, 1841 and Eulaema meriana (Olivier, 1789) were the most common species in the region and, together, represented almost 50% of all collected bees. Although the observed richness conforms to similar inventories in the region, the diversity (H′= 2.43) found in the present study is one of the highest ever recorded for orchid bees in the Amazon Basin.

Frogs have been used as an alternative model to study pain mechanisms because the simplicity of their nervous tissue and the phylogenetic aspect of this question. One of these models is the sciatic nerve transection (SNT), which mimics the clinical symptoms of “phantom limb”, a condition that arises in humans after amputation or transverse spinal lesions. In mammals, the SNT increases glucose metabolism in the central nervous system, and the lactate generated appears to serve as an energy source for nerve cells. An answerable question is whether there is elevated glucose uptake in the dorsal root ganglia (DRG) after peripheral axotomy. As glucose is the major energy substrate for frog nervous tissue, and these animals accumulate lactic acid under some conditions, bullfrogs Lithobates catesbeianus were used to demonstrate the effect of SNT on DRG and spinal cord 1-[14C] 2-deoxy-D-glucose (14C-2-DG) uptake in the presence and absence of lactate. We also investigated the effect of this condition on the formation of 14CO2 from 14C-glucose and 14C-L-lactate, and plasmatic glucose and lactate levels. The 3-O-[14C] methyl-D-glucose (14C-3-OMG) uptake was used to demonstrate the steady-state tissue/medium glucose distribution ratio under these conditions. Three days after SNT, 14C-2-DG uptake increased, but 14C-3-OMG uptake remained steady. The increase in 14C-2-DG uptake was lower when lactate was added to the incubation medium. No change was found in glucose and lactate oxidation after SNT, but lactate and glucose levels in the blood were reduced. Thus, our results showed that SNT increased the glucose metabolism in the frog DRG and spinal cord. The effect of lactate on this uptake suggests that glucose is used in glycolytic pathways after SNT.

Aquatic plants are able to alter their morphology in response to environmental condition variation, such as water level fluctuations. The aim of this study was to evaluate the effect of water level on Sagittaria montevidensis morphology through measures of vegetative structures formed in drought and flood periods. We hypothesised that the plant height and the biomass of S. montevidensis leaves will increase during flood periods, while the biomass and diameter of petioles, and the basal plant area will increase during dry periods. We sampled a total amount of 270 individuals in nine sediment banks per visit, totalling 1080 plants. In order to compare plant morphology between dry and flood periods, we measured the water level in each bank and took the following variables for each plant: diameter, height and diameter of the biggest petiole. In order to compare biomass allocation between dry and flood periods, we sampled a total amount of 90 individuals in nine sediment banks per visit, totalling 360 plants. Plants were dried and weighed in the laboratory. All measured morphologic traits, as well as the biomass of leaf blades and petioles, were higher during flood periods, indicating that water level highly influences the morphology of S. montevidensis individuals. Our results suggest that these morphological responses allow survival and maintenance of S. montevidensis populations under environmental stress. These results can be linked to the invasive potential of S. montevidensis and sheds light on basic management practices that may be applied in the future.

An inventory of the insect gall from Brazilian savanna (Cerrado) was elaborated based on samples of the collection of the Museu Nacional, Universidade Federal do Rio de Janeiro. Data on localities and host plants were obtained from the labels and information about the gall morphology (plant organ of occurrence, shape, and presence of trichomes) by observing the samples. The galling species was determined based on the literature. The collection includes 131 morphotypes of galls from Cerrado, obtained from 71 host plant species distributed in 50 genera and 30 botanical families (Table 1). All galls were collected in rupestrian fields (a rare vegetation physiognomy of the Brazilian Cerrado) in the state of Minas Gerais. As the collection comprises a great diversity of insect galls, it can be considered representative of this physiognomy.

In the context of the modern agriculture, pest control is important in order to increase productivity in maize (Zea maysL.). However, this control should be done rationally, prioritising environmentally safer methods such as biological control. This paper aims to report the occurrence of Dolichozele koebelei Viereck, 1911 (Hymenoptera: Braconidae) in Spodoptera frugiperda(J. E. Smith, 1797) (Lepidoptera: Noctuidae) larvae collected in maize subjected to different cropping systems. The experiment was conducted at the Centro Nacional de Pesquisa de Milho e Sorgo (CNPMS) in Sete Lagoas, Minas Gerais State, Brazil, using organic and conventional production. Ten plants were sampled from each of the 24 plots and for each production system, three times a week during the entire cycle of maize (variety BR 106). In the laboratory, larvae were distributed in individual rearing containers with artificial diet until the end of the biological cycle. An increased number of S. frugiperda larvae was observed in organic single crop maize; hence a higher percentage of S. frugiperda larvae parasitised by Hymenoptera and Diptera also occurred in the maize under this production system. Dolichozele koebelei had not yet been described in association with larvae of S. frugiperda. The percentage of parasitism of S. frugiperda larvae was high in both experiments, indicating the importance of natural control agents in reducing the population density of S. frugiperda, and especially the importance of an appropriate crop management.

This study records, for the first time, the occurrence of all four male morphotypes in a population of Macrobrachium amazonicumfrom a continental environment, with an entirely freshwater life cycle. The specimens studied came from the Tietê River, state of São Paulo, Brazil, and were collected in a lotic environment downstream from Ibitinga Dam. This population was compared with other continental populations, including a population from the dam itself, collected in a previous study. Four samples of 30 minutes were taken monthly, using a trap, from January to April 2011. Each male specimen was measured with respect to seven body dimensions as follows: carapace length (CL), right cheliped length (RCL), dactyl length (DCL), propodus length (PPL), carpus length (CRL), merus length (ML) and ischium length (IL). The relative growth was analyzed based on the change in growth patterns of certain body parts in relation to the independent variable CL. The four male morphotypes proposed for the species were found using morphological and morphometric analyses. Different biological characteristics were found between the populations studied. The male population of the lake of Ibitinga and from Pantanal presented mean sizes and number of morphotypes lower than the population studied here. These differences seem to be closely related to ecological characteristics of the environments inhabited by these populations. Our results supported the hypothesis that coastal and continental populations of M. amazonicum belong to the same species.

No summary/description provided

No summary/description provided

The oligochaetes are considered good indicators of ecological conditions and specific types of habitats. Among the factors that influence the distribution of these invertebrates are the water flow and the nature of the substrate. The aim of this study is to describe the composition and distribution of oligochaete species in a first-order stream in Atlantic Forest and try to identify if some species are associated with characteristics of particular types of habitats. In the dry season and in the rainy season, sand and litter samples in two riffle areas and two pool areas were collected in different parts along the stream using a hand net. The greatest observed richness and abundance occurred in sand in the pool, however the greatest estimated richness was obtained for litter in the pool. The Kruskal-Wallis analysis showed effect of the different types of habitat on the abundance and richness of oligochaetes. The Nonmetric Multidimensional Scaling (NMDS) and Multiresponse Permutation Procedure analysis (MRPP) indicated that the variation in the fauna composition had relation with different types of substrates. The indicator species analysis showed that Limnodrilus. hoffmeisteri was an indicator species in both the riffle sand and pool sand and Pristina americana was only an indicator in the pool sand. The high organic matter content in both sandy habitats probably favored the greater abundance of oligochaetes. The results showed that the substrate constitutes an important factor for the local distribution of these invertebrates in streams. The variation of the community structure among mesohabitats and the presence of indicator species of specific types of habitats in the stream demonstrate the importance of environmental heterogeneity for the oligochaetes fauna in forested streams.

The aim of this study was to determine the lethal salinity (LC50) for the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) and identify histopathological alterations that could be used to diagnose structural changes in clam tissue. Clams in two size classes (adults and juveniles) were placed in 10 L chambers and exposed to salinities of 35, 30, 25, 20, 15, 10, and 5 g/L. There were triplicate chambers with seven clams each for each salinity. The LC50 values for a 48 h exposure were 6.5 g/L and 5.7 g/L for adults and juveniles, respectively. For a 96 h exposure, the LC50 values were 10.5 g/L for adults and 8.8 g/L for juveniles. The histological examination of yellow clams exposed to 10 g/L for 96 h showed intercellular oedema and necrotic foci in the epithelium of the digestive gland and occlusion of the lumen of the digestive gland. In conclusion, M. mactroides can be characterised as a moderately euryhaline species, tolerating salinities from 35 to 15 g/L.

In this study we analyzed diet composition, niche breadth and overlap of the two leaf-litter frogs Ischnocnema henselii and Adenomera marmorata. Frogs were collected in an Atlantic Rainforest area in the Reserva Natural Salto Morato, in Paraná State, Southern Brazil, using plots of 16 m2 established on forest floor. Ischnocnema henselii consumed 18 different types of prey and the diet of this species was composed predominantly by Hymenoptera (Formicidae) (15.4%), Araneae (13.83%), Orthoptera (6.15%) and Opiliones (6.15%), whereas Adenomera marmorata consumed 15 different types of prey and its diet was composed mainly by Hymenoptera (Formicidae) (45.7%), Acari (31.8%) and Blattodea (14.8%). The niche breadth of I. henselii was BA = 0.43 and that of A. marmorata was BA = 0.19. The diet of the two sympatric species of leaf-litter frogs was basically composed by arthropods and the trophic niche overlap among them did not differ from expected at random. The differences in prey consumption should potentially facilitate the coexistence of two sympatric frogs on the forest floor. Possibly, this difference of prey consumption partly reflects differences in jaw width, species-specific body size of the two species and the period of activity of these two species.

In lentic freshwater ecosystems, patterns of thermal stratification play a considerable part in determining the population dynamics of phytoplankton. In this study we investigated how these thermal patterns and the associated hydrodynamic processes affect the vertical distribution of phytoplankton during two consecutive diel cycles in a warm polymictic urban reservoir in the metropolitan region of São Paulo, Brazil. Water samples were taken and physical, chemical and biological data collected at half-meter intervals of depth along a water column at a fixed site, every 3 hours throughout the 48-hour period. Two events of stratification, followed by deepening of the thermocline occurred during the study period and led to changes in the vertical distribution of phytoplankton populations. Aphanocapsa delicatissima Nägeli was the single dominant species throughout the 48-hour period. In the second diel cycle, the density gradient induced by temperature differences avoided the sedimentation of Mougeotia sp. C. Agardh to the deepest layers. On the other hand, Pseudanabaena galeata Böcher remained in the 4.0-5.5 m deep layer. The thermal structure of the water was directly affected by two meteorological factors: air temperature and wind speed. Changes in the cell density and vertical distribution of the phytoplankton were controlled by the thermal and hydrodynamic events.

The objective of this study was to estimate and compare some important reproductive parameters of Myocastor coypus over time (June 2006-May 2008), in wetlands of the Middle Delta of the Paraná River (MD) Entre Ríos province, R. Argentina. Within the original coypu distribution range, the MD is among the areas of highest habitat suitability for the species. Coypus were captured and the following reproductive parameters were estimated on a monthly, seasonal and annual basis: pregnancy rate (PR), litter size (LS), gross productivity (GP) and annual production (AP). Statistical non-parametric tests were used for comparisons. Additionally, the expected birth date of each embryo and fetus was estimated by assigning it to a developmental stage category and considering the gestation period of the species. All the parameters showed high values and PR and LS differed significantly between the dry (2006) and humid years (2007). Two peaks of birth were detected, one in spring and another one in mid-autumn. The implications of these results for ensuring the sustainable management of this rodent are discussed.

Hummingbird communities tend to respond to variation in resources, having a positive relationship between abundance and diversity of food resources and the abundance and/or diversity of hummingbirds. Here we examined the influence of floral resource availability, as well as seasonality and type of habitat on the composition of hummingbird species. The study was carried out in two habitats of eastern Brazilian mountaintops. A gradient representative of the structure of hummingbird community, based on species composition, was obtained by the ordination of samples using the method of non-metric multidimensional scaling. The composition of hummingbird species was influenced by the type of habitat and floral resource availability, but not by seasonality. Hummingbird communities differ between habitats mainly due to the relative abundance of hummingbird species. The variation in composition of hummingbird species with the variation in floral resource availability may be related to differences in feeding habits of hummingbirds. Hummingbird species with the longest bills visited higher proportions of ornithophilous species, while hummingbirds with shorter bills visited higher proportions of non-ornithophilous species. The results demonstrate that at local-scale the composition of hummingbird species is affected by the type of habitat and floral resources availability, but not by seasonality.