Circadian variation with a diurnal bimodal profile on scent-marking behavior in captive common marmosets (callitrhix jacchus)

Scent-marking behavior is associated with different behavioral contexts in callitrichids, including signalizing a territory, location of feeding resources, and social rank. In marmosets and tamarins it is also associated with intersexual communication. Though it appears very important for the daily routine of the individuals, very few researchers have investigated distribution through the 24-h cycle. In a preliminary report, we described a preferential incidence of this behavior 2 h before nocturnal rest in families of common marmosets. We expand the data using 8 family groups (28 subjects), 8 fathers, 6 mothers, 8 nonreproductive adults (4 sons and 4 daughters), and 6 juvenile (3 sons and 3 daughters) offspring that we kept in outdoor cages under natural environmental conditions. We recorded the frequency of anogenital scent marking for each group during the light phase, twice a wk, for 4 consecutive wks, from March 1998 to September 1999. Cosinor test detected 24- and 8-h variations in 89.3% and 85.7% of the subjects, respectively, regardless of sex or reproductive status. The 8-h component is a consequence of the 2 peaks for the behavior, at the beginning and end of the light phase. Daily distribution of scent marking is similar to that others described previously for motor activity in marmosets. The coincident rhythmical patterns for both behaviors seem to be associated with feeding behavior, as described for callitrichids in free-ranging conditions, involving an increase in foraging activities early in the morning and shortly before nocturnal rest

Características limnológicas e estrutura trófica das comunidades de peixes de alguns lagos naturais e artificiais do Rio Grande do Norte

Artificial lakes must differ from natural lakes in important structural and functional aspects that need to be understood so that these ecosystems can be properly managed. The aim of this work was to test the hypothesis that the artificial lakes (impoundments) in the semi-arid region of the Rio Grande do Norte State are more eutrophic and turbid and have different trophic structure when compared to the natural coastal lakes that occur in the humid eastern coast of the State. To test this hypothesis, 10 natural lakes and 8 artificial lakes with about 100 ha were sampled between September and November 2005 for the determination of some limnological variables and the abundance of the main fish species, which were grouped in three trophic guilds: facultative piscivores, facultative planktivores and omnivores. The results show that the artificial lakes had significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a , total and volatile suspended solids than the natural lakes. Results also show that the values of pH, total alkalinity, electric conductivity, turbidity as well as the coefficient of vertical attenuation of light were significantly higher in the artificial lakes than in the natural lakes. In the artificial lakes, the abundance of facultative planktivores was significantly higher, while the abundance of facultative piscivores significantly lower than in the natural lakes. There was no significant difference in the abundance of omnivorous fish between the two types of lakes. These results suggest that the increase in turbidity together with the other changes in the water quality of the artificial lakes, modifies the trophic structure of the fish communities reducing the importance of piscivores and the length of the food chains

Size-related shifts in dietary composition of Centropomus parallelus (Perciformes: Centropomidae) in an estuarine ecosystem of the southeastern coast of Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stomach fullness modulates prey size choice in the frillfin goby, Bathygobius soporator

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

Physiological and morphological responses to feeding in broad-nosed caiman (Caiman latirostris)

Broad nosed caiman are ectotherm sauropsids that naturally experience long fasting intervals. We have studied the postprandial responses by measuring oxygen consumption using respirometry, the size changes of the duodenum, the distal small intestine, and the liver, using repeated non-invasive ultrasonography, and by investigating structural changes on the level of tissues and cells by using light- and electron microscopy. The caimans showed the same rapid and reversible changes of organ size and identical histological features, down to the ultrastructure level, as previously described for other ectothermic sauropsids. We found a configuration change of the mucosa epithelium from pseudostratified during fasting to single layered during digestion, in association with hypertrophy of enterocytes by loading them with lipid droplets. Similar patterns were also found for the hepatocytes of the liver. By placing the results of our study in comparative relationship and by utilizing the phylogenetic bracket of crocodiles, birds and squamates, we suggest that the observed features are plesiomorphic characters of sauropsids. By extending the comparison to anurans, we suggest that morphological and physiological adjustments to feeding and fasting described here may have been a character of early tetrapods. In conclusion, we suggest that the ability to tolerate long fasting intervals and then swallow a single large meal as described for many sit-an-wait foraging sauropsids is a functional feature that was already present in ancestral tetrapods.

Substrate Preparation Behaviors for the Cultivation of the Symbiotic Fungus in Leaf-Cutting Ants of the Genus Atta (Hymenoptera: Formicidae)

Our findings revealed two distinct patterns of substrate preparation: the pattern of leaf-cutting ants foraging on dicotyledons is marked by highly fragmented substrate resulting in a more advanced initial decomposition. The pattern of leaf-cutting ants harvesting grasses is characterized by large pieces of substrate, resulting in little initial decomposition. Ants foraging on both types of plants are apparently intermediary between the two patterns, although more similar to the patterns of those foraging on dicotyledons. Also, the behavior of scraping the substrate was described for the first time, it is very important for the removal of the epicuticular wax layer of the leaves helping the growth of the symbiotic fungus.

Preliminary studies on the effects of d-limonene to workers of the leaf-cutting ant Atta sexdens rubropilosa and its implications for control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Survey of preys captured and used by Polybia platycephala (Richards) (Hymenoptera: Vespidae, Epiponini)

As vespas sociais são predadoras de várias espécies de insetos e, portanto, o estudo de suas presas pode revelar seu potencial para programas de controle biológico de pragas. Durante o período de setembro de 2000 a janeiro de 2002, foram realizadas 70h de coleta de presas capturadas em doze ninhos de Polybia platycephala Richards, localizados em áreas urbanas do município de Juiz de Fora, MG. As presas capturadas por P. platycephala compreenderam cinco ordens de insetos: Diptera (33,4%), Lepidoptera (28,6%), Hemiptera (12,0%), Hymenoptera (9,4%) e Coleoptera (7,2%). O peso médio da carga protéica transportada pelas vespas foi 1,9 ±1,6 mg (n = 34, 0,3 - 6,2 mg), e a taxa média de proteína transportada por dia foi 22,8 mg. de acordo com os resultados, pode-se estimar a captura de 4.380 presas por ano por uma única colônia de P. platycephala. Desta forma, a espécie pode ser utilizada em programas de manejo em ambientes urbanos contribuindo para o controle de insetos pragas como larvas de pernilongos, lagartas desfolhadoras de plantas de jardins, pulgões e formas aladas de formigas.

Prey captured and used in Polistes versicolor (Olivier) (Hymenoptera: Vespidae) Nourishment

As vespas sociais são predadoras de muitas espécies de insetos e o estudo de suas presas pode revelar seu potencial para programas de controle biológico de pragas. Foram realizadas 240h de coleta de presas em 32 colônias de Polistes versicolor (Olivier) no município de Juiz de Fora, MG, de março de 2000 a fevereiro de 2001. As presas capturadas por P. versicolor foram, principalmente, das ordens Lepidoptera (95,4%) e Coleoptera (1,1%) além de 3,4% de indivíduos não identificados. A espécie mais coletada foi Chlosyne lacinia saundersii Doubleday & Hewitson (13,5%) (Lepidoptera: Nymphalidae) e o número total estimado de presas capturadas por colônia de P. versicolor foi de 4.015 indivíduos por ano. Isso mostra que a espécie pode ser utilizada em programas de manejo integrado de pragas de insetos herbívoros, principalmente lagartas desfolhadoras.

Entomofauna visitante de Stenolobium stans (Juss.) Seem (Bignoniaceae), durante seu período de floração

Realizaram-se estudos sobre as formas de reprodução de Stenolobium stans (Juss.) Seem e determinou-se a diversidade, freqüência e constância dos insetos visitantes nas flores em diferentes horas, durante quatro anos. As flores de S. stans começam a se abrir nas primeiras horas do dia entre 5 e 6h, com duração de 3 a 8h. Quando o estigma está receptivo, o pólen tem 90% de viabilidade. Além do pólen, a flor possui outros atrativos para os insetos visitantes, ou seja, os osmóforos responsáveis pelo odor adocicado, luz ultravioleta refletida e néctar com 25% de açúcar. A planta é autocompatível, reproduzindo-se por autogamia, geitonogamia ou xenogamia o que determina a necessidade de polinizadores externos e justifica ser a espécie vegetal em estudo uma séria invasora de campos e pastagens. Grande diversidade de insetos foi verificada visitando as flores, com predominância das abelhas. Os polinizadores foram Centris collaris Lepeletier, Bombus morio (Swederus), Eulaema nigrita Lepeletier e Epicharis sp. No meio rural houve menor incidência das espécies nativas do que no ambiente urbano, com predominância da abelha introduzida Apis mellifera L. Fatores ambientais, principalmente a temperatura, luminosidade, umidade relativa do ar e velocidade do vento, influenciaram a atividade forrageadora dos insetos.

Visitantes florais de Lagerstroemia speciosa Pers: (Lythraceae)

Studies were carried out with Lagerstroemia speciosa Pers. on floral reproductive systems, diversity and constancy of visiting insects at different hours of day, the behaviour of these insects at the flowers and the influence of these environmental factors in relation to their visits. The fenology, anthesis and others particularity of this vegetal species was studied. A great diversity of insects was verified visiting the flowers with the predominance of bees. The most frequent and constant species encountered were: Nannotrigona testaceicornis (Lepeletier, 1836) (40,2%), Tetragonisca angustula (Latreille, 1811) (16,9%), Apis mellifera Linnaeus, 1758 (11,8%), Plebeia droryana (Friese, 1900) (9,1 %) e Exomalopsis fulvofasciata (Smith, 1879) (8,5%). The blossoms possessis features of melittophily syndrome and diurnal anthesis. The environmental factors influence the insects foraging activity, mainly temperature, light, time of day, humidity and wind speed. The effective pollinators were the large insects like Bombus morio (Swederus, 1787), Bombus atratus (Franklin, 1913), Centris tarsata (Smith, 1874), Centris flavifrons Fabricius, 1775, Xylocopa suspecta Camargo & Moure, 1988, Xylocopa frontalis (Olivier, 1789) and Eulaema nigrita Lepeletier, 1841.

A diversidade de lagartos na Caatinga é mediada pelos térmitas?

Intending to explain the extraordinary lizard coexistence levels found in Australian deserts, Morton & James (1988) figured out a hypothesis which defends that the termite diversity would bring about lizard radiation. This study aims to verify the validation of that hypothesis in Caatinga lizard assemblages. This study also objectives verifying if the termite defense mechanisms influence their consuming levels by lizards and if this pattern differs between different lizard lineages. Termites were collected using a standardized sampling protocol of termites. Besides using haphazard sampling, we collect lizards with 108 pitfall traps in each area. Intending to check the linkage between the termite and lizard assemblages, the lizard stomach contents were analyzed and then a canonical correspondence analysis was performed. The presence of nonrandom patterns of diet overlap among the lizard species was also examined. Aiming to check if the defense mechanisms of termite influence their consuming pattern by lizards it was performed a laboratory experiment where termite with different defense mechanisms were offered to lizards of two different lineages. We verified that lizard assemblages do not consume termites according to termite abundance in ecosystems. Furthermore, mean niche overlap lizard species did not differ significantly from that expected by chance. We found that termite chemical defense mechanism does influence the termite s pattern consuming by lizards. These results do not corroborate premises which support Morton & James hypothesis (1988) and point out that lizard do not chose termites based on their abundance, but, trying to avoid consuming termites which exhibit chemical defense mechanisms. This defense mechanism, however, may not be the only explanation to patterns of termite s consuming by lizards.

Caracterização do nicho alimentar do polvo octopus insularis (cephalopoda: octopodidae): da população ao indivíduo

Octopus insularis, target species in this study, is the dominant benthic octopus of the North and Northeast Brazil. Studies on behavior and ecology of the species have been conducted primarily on oceanic islands, with little information on the continental populations. In this study, two regions of the coast of RN, Rio do Fogo and Pirangi, were chosen for the characterization of the niche by O. insularis populations. The dietary niche, habitat and distribution of O. insularis of oceanic islands and the mainland, were compared. In addition, individual characteristics of feeding behavior in a population at Atol das Rocas was studied, taking into account the size of individuals, the proximity of the dens and characteristics of their "personality". The diet of the Rio do Fogo population was composed mainly of bivalve molluscs (82%), unlike Pirangi population that has a diet consisting mainly of crustaceans Decapoda (68%), similar to that described for the populations of the islands. Consequently, the feeding niches of the island populations were more similar, with greater overlap, but the niche breadth of the continent was larger. The habitats of occurrence on the coast includes reefs, rocks, gravel and an environment called Restinga, a plateau composed of biogenic gravel, sand, sponges and algae, showed a high density of animals. Similarly to that found in the islands, O. insularis in the continent, had a clumped distribution, and a bathymetric segregation between small and large individuals. The differences in diet composition among populations were explained by differences in habitat and coverage of the substrate, which may be directly influencing the diversity and prey availability in these environments. The individual analyzes of the population at Atol das Rocas, showed no relationship between the degree of individual specialization and the different personalities, or the distance between dens. The results suggest that the foraging strategy with greater availability of prey in the environment has an influence on diet octopuses over preferences or personalities

O histórico de uma pesca tropical utilizando indicadores ecossistêmicos

When scientists study methods, theory and standards in an inseparable form, he is facing a paradigm. Throughout the development of a determined science, paradigms can change by changing the methods, objective and standards of research. Fisheries science is changing the paradigm moving from the paradigm of maximization in the use of resources, quantified by the index of the catch, which was influenced by evolutionary concepts such as Optimal Foraging Theory, to the sustainability paradigm that seeks its foundation in the fishery ecosystem perspective. The goal of this study was to review methods, theory and the history of ecosystem indexes of fishery science that attempts to determine sustainability of fishery resources from the data capture. Ecosystems indexes by themselves may not be useful to measure the sustainability of fishing because they focus only on the environmental or ecological side of the sustainability tripod. Probably to measure the sustainability of fishing these indexes should include in the future the Payments for Ecosystem Services and Social Resilience. Thus the methods and theories are in constantly changing within science to meet the most current paradigm

Os efeitos da estrutura de habitat sobre as comunidades de aranhas em uma floresta de caatinga do nordeste brasileiro

The inherent complexity of natural communities is a challenge to our understanding about how the habitat influences the abundance, local distribution and species diversity. The habitat can influence community structure in multiple ways and elucidate these relationships has provoked a lot of debate in ecology. The habitat heterogeneity hypothesis states that an increase in habitat heterogeneity (number of habitats) leads to an increase in species diversity in the landscape due to an expansion in niche dimensions. This study aims to identify whether this hypothesis is valid for the spiders that inhabit a locality in the Caatinga of northeastern Brazil. Cursorial and arboreal spiders were sampled in 30 plots within an area of Caatinga together with measures of environmental complexity, habitat heterogeneity and environmental parameters related to multiple aspects of vegetation architecture and species composition of woody plants. Stepwise multiple regressions were used to define which local environmental parameters best explain the variation in arboreal and cursorial spiders richness. Then a NMDS (Nonmetric multidimensional scaling) was used to reduce the number of predictive variables to those who are the most important and best represent the variation in spiders richness associated with the environment they were sampled. The results show a clear segregation between the guilds of arboreal and cursorial spiders, both related to what kind of environmental variables best explain its variation as well as in relation to what part of the vegetation they occupy