RCAAP Repository

We examined the stomach contents of 21 specimens of Mabuya agilis (Sauria; Scincidae) collected during February 2001 at the restinga habitat of Praia do Sul, in Ilha Grande, RJ, Brazil. Diet was composed of various types of small arthropods, with no plant material being eaten. Spiders were the most important items in the diet, followed by orthopterans. Apart from the absence of isopterans, the diet of Mabuya agilis from this insular area was similar to those of other conspecific mainland populations. This suggests that factors such as insularity and the absence of other small sympatric lizards may not have a significant effect on the feeding habits of the Praia do Sul population.

With the objective of investigating the taxa of Cosmarium, four collection stations along the Corumbá Reservoir were set up. This resulted in the first work done on the genus in the State of Goiás. The collections of the material, of the epilithon type, were carried out in July 1996 and in the period between December 1996 and July 1997. The samples were preserved with 0.5% acetic lugol. The qualitative analysis was done by optical microscopic on non-permanent slides. Twenty-one taxa of the Cosmarium were described, each one illustrated by means of a camera lucida attachment.

Eurema elathea adults were censused weekly (1992-1994) in six night-roosts around a forest fragment on a farm, and in two roosts in the urban area of Uberlândia, Minas Gerais, Brazil. Males were grouped in six phenotypic classes. These were based on a range between having a conspicuous wide black bar at the dorsal forewing inner margin (wet season dark morphs) and the absence of that bar (dry season light morphs). The body mass and wing area of co-occurring morphs were compared: differents morphs showed similar means. The abundance of butterflies and morph frequencies varied in close relation to humidity (rainfall). Individuals were infrequent and monomorphically dark in the wet season while light morphs predominated in dry periods when population peaked. A lower fraction of recaptured individuals and higher recruitment were recorded compared to other night-roosting butterflies. Dispersal potential was similar between the sexes and varied seasonally with a more sedentary population in dry periods. The maximum residence time recorded was 91 days for a female and 84 days for a male. The fraction of individuals that moved from one roosting site to another was similar in both sexes and male morphs, but significantly higher on the farm than in the urban area. Also, a significantly higher fraction (21.3%) of marked butterflies was recaptured in the urban area than on the farm (15.6%), suggesting a behavioral modification for sedentariness in the urban individuals. The selective forces shaping a gregarious roosting habit in E. elathea and other butterflies are discussed and a protocooperational strategy for saving energy is proposed.

Predaceous fish-eating species of the order Clupeiformes have a large mouth with well-developed teeth, and reach the greatest sizes within their families (up to 90 cm). We found that the pristigasterid Chirocentrodon bleekerianus, a small clupeiform (about 10 cm) from the tropical SW Atlantic, is able to prey on proportionally large clupeoid fishes and caridean shrimps. Fish preys are folded in the stomach of this herring, their heads and tails pointing toward the predator's head. This distinctive orientation of fish prey is also recorded for some small to medium-sized, fish-eating species of the tropical freshwater order Characiformes with canine-like teeth similar to those found in C. bleekerianus.

Between March 2000 and April 2001, 63 specimens of N. barba from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23°0'S, 44°19'W), Brazil, were necropsied to study their infracommunities of metazoan parasites. Fifteen species of metazoan parasites were collected: 2 digeneans, 1 monogenean, 2 cestodes, 1 acantocephalan, 2 nematodes, 6 copepods, and 1 hirudinean. Ninety-six percent of the catfishes were parasitized by at least one metazoan parasite species. A total of 646 individual parasites was collected, with mean of 10.3 ± 16.6 parasites/fish. The copepods were 37.5% of the total parasite specimens collected. Lepeophtheirus monacanthus was the most dominant species and the only species with abundance positively correlated with the host total length. Host sex did not influence parasite prevalence or mean abundance of any species. The mean diversity in the infracommunities of N. barba was H = 0.130 ± 0.115 with no correlation with host's total length and without differences in relation to sex of the host. One pair of endoparasites (Dinosoma clupeola and Pseudoacanthostomum floridensis) showed positive association and covariation between their abundances and prevalences. The parasite community of N. barba from Rio de Janeiro can be defined as a complex of species with low prevalence and abundance and with scarcity of interspecific associations. However, because of both the presence of assemblages of sympatric ariid species as well as the spawning behavior characteristic of these fishes, additional comparative studies of the parasite component communities of ariids are necessaries to elucidate this pattern.

This paper describes and discusses the impacts of the passage of cold fronts on the vertical structure of the Carlos Botelho (Lobo-Broa) Reservoir as demonstrated by changes in physical, chemical, and biological variables. The data were obtained with a continuous system measuring 9 variables in vertical profiles in the deepest point of the reservoir (12 m) coupled with climatological information and satellite images, during a 32-day period in July and August, 2003. During periods of incidence of cold fronts the reservoir presented vertical mixing. After the dissipation of the cold fronts a period of stability followed with thermal, chemical, and biological (chlorophyll-a) stratification. Climatological data obtained during the cold front passage showed lower air temperature, higher wind speed and lower solar radiation. The response of this reservoir can exemplify a generalized process in all shallow reservoirs in the Southeast Brazil and could have several implications for management, particularly in relation to the phytoplankton population dynamics and development of cyanobacterial blooms. Using this as a basis, a predictive model will be developed with the aim of advancing management strategies specially for the drinking water reservoirs of the Metropolitan Region of São Paulo.

One aspect of plant defense is the production of constitutive secondary compounds that confer toxicity on herbivores and pathogens. The purpose of this study was to compare patterns of plant tissue toxicity across gradients of irradiance and nutrient content. We measured the potential toxicity (1/LC50) of extracts of six species of herbaceous Asteraceae grown under controlled conditions of temperature (25ºC), humidity (80%), photoperiod (16 h/day), in a range of concentrations of a modified Hoagland hydroponic solution (full-strength, 1/5 dilute, 1/10 dilute, and 1/50 dilute) and under two different light intensities (250 and 125 mumol/m²/s). The plants grew from seed for 42 days post-germination, and randomly chosen plants were harvested each 7 days. We did a general measure of potential phytochemical toxicity using an alcohol extraction of secondary compounds followed by brine shrimp (Artemia sp.) bioassay. Contrary to the carbon/nutrient balance hypothesis, tissue toxicity generally increased with decreasing irradiance and nutrient levels, so that plants whose growth was most restricted had tissues that were most toxic, although there were species-specific differences in this trend.

With the purpose of determining the principal food resources responsible for maintaining the fishery yield in a section of the São Francisco River, 6 sampling of the fish fauna were made downstream from the Três Marias Dam, from September 1996 to July 1997. A total of 1,127 individuals of 35 species were captured, using gillnets with mesh sizes varying from 3 to 16 cm. The stomach contents of 33 species were examined in order to determine their diets. Five trophic guilds were established, in the following order of importance: ilyophagous, herbivorous, piscivorous, terrestrial invertebrates feeders, and aquatic invertebrates feeders. The resources sustaining the fish fauna were mainly of allochthonous origin. The ichthyonenosis appears to be mainly dependent on the detritus chain. The ciliary forest and seasonal flooding pulses are the main suppliers of food for the fish fauna.

We used Raunkiaer's system to classify in life-forms the vascular plants present in 12 random 25 m² quadrats of a cerrado site. The study area is covered by cerrado sensu stricto and is located in the Valério fragment, at about 22º13'S and 47º51'W, 760 m above sea level, in the Itirapina Ecological and Experimental Station, São Paulo State, southeastern Brazil. The floristic spectrum considers the life-form of each species, while in the frequency spectrum, each species is weighted by its frequency. The vegetation spectrum does not consider the species at all, but only the individuals in each life-form class. In the floristic spectrum, the most represented life-forms were the phanerophytes and the hemicryptophytes, as in other cerrado sites. This spectrum differed significantly from Raunkiaer's normal spectrum, mainly due to under-representation of therophytes and over-representation of phanerophytes. The floristic and frequency spectra were similar, but both differed from the vegetation spectrum. We recommend the floristic spectrum when working at larger scales and a description of the phytoclimate is wanted. The vegetation spectrum is preferable when working at smaller scales and wanting a quantitative description of the physiognomy. The frequency spectrum is not recommended at all.

Final oocyte maturation (FOM) is a process involving a complex set of genetical, biochemical, and morphological mechanisms. FOM involves the shift of a post-vitellogenic follicle to a pre-ovulated oocyte, which is necessary for fertilization by spermatozoan to occur. This process is regulated by a maturation-inducing steroid (MIS) at the follicular level. In other species of scienids fish the MIS, a hydroxilated derivatives of progestagen 17, 20beta, 21-trihydroxy-4-pregnen-3-one (20beta-S), was identified. Although Micropogonias furnieri is the second fishery resource of Uruguay, basic knowledge about its endocrine process is very scarce. The aim of this work was to investigate what steroids are synthesized in vitro by the oocyte follicle of M. furnieri during the maturation process. Fragments of ovary (1 g) in three stages: post-vitellogenic (PV), maturing (Mtg), and mature (M) were incubated with 1 mug.g-1 of tritiated progesterone (P) at 30, 60, and 180 min. After extraction with ethanol and dichloromethane, steroid metabolites were purified by TLC and rpHPLC. Two progesterone derivatives with identical chromatographic properties of 20beta-S and 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P) were purified. In other Teleost fish these steroids are biologically activ as MIS. The 17,20beta-P was clearly detected in Mtg and M stages and confirmed by enzymatic oxidation with enzyme 20beta-HSD. The 20beta-S was strongly detected in all Mtg oocytes. The results do not corroborate 20beta-S as a major hormone synthesized in the ovary in FOM as occurs in other scienid fish. A differential steroid synthesis in the advanced oocyte stages suggests that the 20beta-S is acting as a MIS in M. furnieri.

A short characterization of Macrothrix flabelligera Smirnov, 1992 (Cladocera, Macrothricidae) is presented, following a recent record of this species in Brazil. General aspects and morphological details of the body of parthenogenetic and ephippial females, as well as of males, are described and illustrated.

Lutzomyia umbratilis is the main vector of cutaneous leishmaniasis due to Leishmania guyanensis in northern South America. It has been found naturally infected with this species of Leishmania only east of the Rio Negro and north of the Rio Amazonas. However, populations of this sand fly species are also present in areas south of the Amazon river system, which may act as a geographical barrier to the Leishmania guyanensis cycle. With the aim of looking for possible biological differences between populations of L. umbratilis from each side of this river system, their biology in the laboratory was investigated. Progenitors collected on tree bases in Manaus and Manacapuru (east and west, respectively, of the Rio Negro) were reared in the laboratory. Results from observations of the life cycle, fecundity, fertility, and adult longevity at 27ºC and 92% RH were analyzed by descriptive statistics and z, t, U, and chi2 tests. Although the Manaus and Manacapuru colonies showed a longer developmental time than most Lutzomyia species reared at similar temperatures, length of time of egg and 4th instar larva of the two populations differed significantly (p < 0.01). Females of the latter retained significantly (p < 0.001) less mature oocytes, and the general productivity (% adults from a known number of eggs) of the colony was significantly (p < 0.01) higher than that of the former. These results show that the L. umbratilis population of Manaus is more productive, and thus a better candidate for future mass-rearing attempts. The two populations differ in their life cycle, fecundity, fertility, adult longevity, and emergence. These differences may reflect some divergence of intrinsic biological features evolved as a result of their geographical isolation by the Rio Negro. It is expected that further investigations on morphometry, cuticular hydrocarbon, isoenzyme, molecular and chromossomal analyses, infection, and cross-mating experiments with these and other allopatric populations of both margins of the Amazon river system will help reveal whether or not L. umbratilis has genetically diverged into two or more reproductively isolated populations of vectors or non-vectors of Leishmania guyanensis.

Biological control has been reducing the use of chemical products against insect pests, specially predatory Pentatomidae. Species of this group can present high variations in their life cycle as a result of their diet. Thus, the objective of this research was to study nymph development and reproduction of Podisus distinctus (Stäl, 1860) (Heteroptera: Pentatomidae) fed on Bombyx mori L., 1758 (Lepidoptera: Bombycidae) larvae (T1), compared to those fed on Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) (T2) and Musca domestica L., 1758 (Diptera: Muscidae) larvae (T3) at a temperature of 25 ± 0.5ºC, relative humidity of 70 ± 2%, and photophase of 12 h. Predators fed on B. mori showed duration of the nymph phase (18.68 ± 1.02) similar to those fed on T. molitor (18.32 ± 1.49). Pre-oviposition and oviposition periods and number of egg masses, besides eggs and nymphs per female, were higher with B. mori (5.83 ± 2.02; 15.00 ± 7.40; 8.42 ± 1.84; 296.69 ± 154.75; and 228.55 ± 141.04, respectively) while longevity of males and females of P. distinctus was 25.76 ± 16.15 and 35.00 ± 16.15 days with T. molitor, and 20.57 ± 13.60 and 23.46 ± 12.35 days with B. mori, respectively.

In this paper we calculate the values of eight pattern detection indices, using different quadrat sizes where individuals of angico above 1.5 m were located, in order to examine their statistical behaviour with increasing sample size. It was concluded that the best index is the standardized Morisita index (Ip) which is completely independent of sample size.

The insect marking technique of Tadei &amp; Mourão (1976) is until now the only experimental method allowing real-age determination of each individual in a population and, consequently, determination of age structure in a given population. We propose an improvement of this technique, used here to determine the population age structure of the geographical strain SR of the Megaselia scalaris Loew (Diptera; Phoridae), maintained by serial transfer technique at constant temperatures 25 ± 1.0ºC and 20 ± 1.0ºC. Determining the age structure allowed the calculation of the real longevity of the flies and the identification of the effect of temperature decisive factors in these are the technique of marking insects, because otherwise we would only have an estimate, and depending on mistakes there in, the effect of the determinant factor (temperature) cannot be detected.

The age and growth of the pintado Pseudoplatystoma corruscans were studied during the period from May 1994 to May 1995. The standard length ranged from 52 to 145 cm and the weight from 1.3 to 41 kg. The biometric relationship between the standard length (Ls) and total length (Ltotal) and between the total weight (Wt) and the standard length (Ls) were obtained for the species, being respectively: Ltotal = 3.296 + 1.069 * Ls and Wt = 0.00624 * Ls3.134.The condition factor calculated monthly suggests the spawning season to be between the months of February and March. The age was estimated by counting growth rings present in the spines of the pectoral fins, and 10 age classes were detected. The mean distance of the last ring until the border of the spine suggests that the period of least growth is between July and September (dry period). Von Bertalaffy's equation describing the growth of the pintado is: Lt = 183 * [1 - exp - 0.085 * (t + 3.274)]. Total mortality was Z = 0.24 year-1 and natural mortality M = 0.20 year-1. As the present level of exploitation, F = Z - M = 0.04 year-1, we conclude that the pintado stock was still underexploited in the Pantanal in the sampled period.

Increased environmental pH decreases ammonia transport through the gills, impairing nitrogenous waste. The consequent toxicity is usually drastic to most fishes. A few species are able to synthesize urea as a way to detoxify plasma ammonia. We studied three teleosts of the family Erythrinidae living in distinct environments, and assumed the biochemical behaviors would be different in spite of their being closely related species. Adult fish collected in the wild were submitted to alkaline water and the urea excretion rate was determined. The specific activity of urea cycle enzymes was determined in liver samples of fish from neutral waters. The studied species Hoplias lacerdae, Hoplerithrynus unitaeniatus, and Hoplias malabaricus are ureogenic. Urea synthesis is not a metabolic way to detoxify ammonia in H. lacerdae and Hoplerithrynus unitaeniatus exposed to an alkaline environment. The plasma ammonia profile of both species showed two distinct biochemical responses. Urea excretion of H. malabaricus was high in alkaline water, and the transition to ureotelism is proposed. The nitrogen excretion rate of H. malabaricus was among the highest values reported and the high urea excretion leads us to include this species as ureotelic in alkaline water.

Electrokinetic, thermic, and kinetic properties of products of NADP-dependent isocitrate dehydrogenase (IDHP; EC 1.1.1.42) loci of Astyanax scabripinnis (Pisces, Characidae) collected at three different altitudes (700 m, 1,800 m, and 1,920 m) of Grande Stream at Campos do Jordão, State of São Paulo, Brazil, were analyzed. Two IDHP bidirectionally divergent loci, a single skeletal muscle, the IDHP-A*, and a single liver IDHP-B*, both polymorphic, were detected in the three different altitude populations. The variant allele *128 at the IDHP-A* locus, had its highest frequency detected in the 1,920 m population (0.494). Among the nine variant alleles detected at the IDHP-B* locus (*37, *57, *69, *79, *85, *114, *119, *124, and *140), the *37 and 79 were detected only in 1,800 m population. Chi-square values showed that only the 700 m population is not in Hardy-Weinberg equilibrium for the IDHP-A* locus, while for the IDHP-B* locus, no population is. Homogeneity Chi² test indicated that the populations are significantly different in their A and B phenotype frequencies. Wright's FST mean value (0.036 and 0.32, IDHP-A* and IDHP-B*, respectively) was 0.178 for the three altitude populations which means that 82% of total genetic diversity was found among individuals of each one of the populations. Stability at environmental temperatures (16º to 21ºC), and apparent Km and Vmax values of each A-phenotype skeletal muscle crude extract suggest different roles of A-isoforms during the increased lipogenesis that occurs in fish at low temperatures.

Observations of the feeding behavior of Cirriformia filigera (Delle Chiaje, 1825) (Annelida: Polychaeta) from the intertidal zone of São Francisco and Engenho D'água beaches (São Sebastião, State of São Paulo) were made in the laboratory. This species, like other cirratulids, is a deposit feeder, feeding mainly on sediment surface with the aid of its grooved and ciliated palps, which are used to capture food particles. The worm lies just beneath the substrate surface in a J-shaped tube. When feeding, it extends up to 4 palps over the sediment surface, capturing food particles which pass down the groove of each palp directly to the mouth. Only fine sand grains are ingested. The worm frequently extends 4 branchial filaments into the overlying water for aeration. When it moves with the prostomium sideways, it collects and transports sand grains that pass backwards along its ventral region until reaching the middle part of its body. Next, the parapodia and palps move the sand grains to the dorsal posterior end of the animal, covering this area with sand. Some sand grains are also ingested as the worm moves.

A comparison between two studies on diel vertical migration of two cyclopoid copepod species, in Lake Monte Alegre, undertaken in 1985/86 and 1999, revealed a change in their migratory behavior. In summer, during a period of marked stratification with low dissolved oxygen near the bottom, the organisms avoided the deepest layers, and migration was nocturnal or undetectable, in both periods. On other occasions, with partial or total circulation in the lake, a weak twilight migration of copepodites and adults in 1985 was replaced by the reverse in 1999. Differences were found among stages, with the weakest or undetectable migration being observed for nauplii. The migratory pattern change for copepodites and adults might be related with a recent predation pressure increase by Chaoborus larvae on copepods, after the virtual disappearance of their main cladoceran prey.