General behavioral patterns and life-cycle of the colonial spider, Eriophora bistriata (Araneida: Argiopidae)

Neste estudo, apresentamos observações preliminares do comportamento e biologia da aranha gregária Eriophora bistriata. O trabalho inclui aspectos da organização social, obtidos através de estudos de laboratório e campo. São inicialmente descritos, além do ciclo básico, algumas interações como: construção de teia comum de caça, ausência de hostilidade inter-individual, alimentação comunal, comportamento reprodutor etc. Os resultados obtidos permitiram comparar Eriophora bistriata, com outras espécies gregárias segundo o esquema evolutivo de Shear (1970: pag. 73)

Cultivares na dieta de macacos-prego barbados, Cebus libidinosus Spix (Primates: Cebidae), em fragmentos florestais no sudeste do Brasil

Capuchin monkeys occupy a wide range of habitats where they feed on fruits, arthropods, and vertebrates. Their large home ranges (80-900 ha) suggest that living in forest fragments may challenge their adaptability. We identified and quantified the main food items of Cebus libidinosus Spix, 1823 in forests fragments (100 ha) in southeastern Brazil. We recorded the feeding activities of two groups using scan sampling over a 13-month period. The diet was composed of fruits, crops, animal prey, seeds, plant matter and undetermined. Fruit was eaten more in the wet season than in the dry season, and maize and sugar cane consumption peaked in the early dry season. The proportion of fruit in the diet was positively correlated with fruiting intensity of zoochorous trees. The plant diet included 54 species, with maize, Rhamnidium elaeocarpus, Acrocomia aculeata, Guazuma ulmifolia and Cariniana, being most important. Although dietary composition and diversity were similar to capuchins in larger forest fragments, feeding on crops attained higher percentages at times when zoochorous fruit production was low in fragments.Macacos-prego ocupam uma vasta gama de ambientes onde alimentam-se de frutos, artrópodes e vertebrados. Suas grandes áreas de vida (80-900 ha) sugerem que viver em fragmentos florestais pode ser um desafio a sua adaptabilidade. Foram identificados e quantificados os principais itens alimentares de Cebus libidinosus Spix, 1823 em fragmentos florestais (100 ha) no sudeste do Brasil. Registraram-se as atividades alimentares de dois grupos usando a varredura instantânea durante um período de 13 meses. A dieta compôs-se de frutos, presas animais, cultivares, sementes, material vegetal e indeterminado. Os frutos foram consumidos mais na estação chuvosa do que na estação seca e o consumo de milho e cana atingiu um pico no início da estação seca. A proporção de frutos na dieta foi positivamente correlacionada com a intensidade de frutificação das árvores zoocóricas. A dieta vegetal incluiu 54 espécies, com milho, Rhamnidium elaeocarpus, Acrocomia aculeata, Guazuma ulmifolia e Cariniana, sendo os mais importantes. Embora a composição da dieta e a diversidade tenham sido similares a grupos de macacos-prego em grandes fragmentos florestais, o uso de cultivares atingiu altas porcentagens em épocas quando a produção de frutos zoocóricos foi baixa nos fragmentos.3239Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Morfometria dos estágios imaturos de Polistes simillimus Zikán, 1951 (Hymenoptera, Vespidae)

The social wasp Polistes simillimus Zikán, 1951 present nests constituted by an only comb arrested to the substratum for an only eccentric peduncle, could stay in the environment for more than one year. The objective of this work was to determine the morfometry of the immature forms of P. simillimus. Were analyzed 127 eggs, 440 larvae and 42 pupae from seven colonies of P. simillimus, collected in Piracicaba, SP. The eggs are white, prolonged and smoothly curved, with 1,18 ±0,08(0,09-1,45) length mm and 0,52 ±0,05(0,42-1,45) width mm. The widths of the cephalic capsules of the larvae proved the existence of five instars, with a reason of growth of 1,44. The larvae of first, second and third instars have thebody arrested inside the old egg, for which are fastened in the cells. The larvae of fourth and fifth instars are larger and fill all the interior of the cell with your bodies. The larva of fifth instar makes a silk cocoon, in which the pupa suffers metamorphosis. In that phase it happens the development of the appendixes and corporal structures, the exoskeleton becomes rigidand with dark coloration. The medium width of the cephalic capsule of the pupas was 2,53 ±0,17(2-2,88)mm. This way, P. simillimus has a development of the type holometabola, whose larvae have five instars, characterizing the post-embryonic development of Hymenoptera

Patterns of honey storage in nests of the neotropical paper wasp Polistes simillimus Zikán, 1951 (Hymenoptera, Vespidae)

This study describes, for the first time, the occurrence of two patterns of honey storage in nests of the paper wasp Polistes simillimus. During the period of January of 1997 to September of 2000 we visited 262 colonies of P. simillimus, found at several places in States of São Paulo and Minas Gerais, in the southeast region of Brazil. Only in 2.67% of the colonies of P. simillimus searched presented the behavior of honey storage. Two of these colonies were in the pre-emergency phase, two in the post-emergency and three in decline. The results suggest that the honey storage can be correlated with the number of present individuals in the colony, because the colonies in decline, with larger number of individuals, presented many more cells occupied with honey than the nests in pre and post-emergency. There was not a pattern for the distribution of the cells with honey in the nests in decline. The honey storage in the colonies in pre and post-emergency of P. simillimus, suggests a strategy to increase success of foraging activity in the function of parental care. Already for the colonies in decline, this strategy seems to be associated with the individuals' survival in the aggregation, since the wasps are awaiting the passage of the unfavorable climatic conditions for the dispersion and foundation of new colonies

Flight range extension in Polistes simillimus Zikán, 1951 (Hymenoptera, Vespidae)

The aim of this study was to determine the flight range extension of the social wasps, Polistes simillimus. The results of the 125 wasps-carried out tests originating from 10 colonies in post-emergency stage demonstrated that the flight range extension of P. simillimus was of approximately 150m, resulting in a collection area of about 70.650m2 by colony. It suggested wasp's efficiency as a biological control agent

Nesting habits and colonial productivity of Polistes canadensis canadensis (L.) (Hymenoptera-Vespidae) in a Caatinga area, Bahia State Brazil

The paper aims at increasing the knowledge on the ecology of Polistes canadensis canadensis colonies in a Caatinga region. We studied some aspects of P.c. canadensis nesting habitats and colonial productivity. In the environmental conditions studied, this species nests on several types of substrata, particulary on thorny plants and in caves. The colony productivity and the cell reoccupation rate varies from one colony to another. In some colonies, we found cells with one, two and, more rarely, three reoccupations, this is upto four individuals produced in one cell only. The rate of the first reoccupation was 2.88-34.78%, with na average rate of 15.96%. The number of adults produced by the colonies of Flc, canadensis varied from 10 to 576 individuals. Productivity, given by the relationship between the number of born adults and the number of cell existing in the nest, varied from 31.25 to 123.19% and presented an average of 88.50%