Dispersion of Seeds of Tree Species by the Leaf-Cutting Ant Acromyrmex subterraneus molestans (Hymenoptera: Formicidae) in Vicosa, Minas Gerais State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation and development of passion fruit (Passiflora alata Dryander) propagated by cutting and seet in conditions of commercial orchard

The present work was conducted in a fruit tree propagation area of the Plant Production Department of the Faculdade de Ciencias Agrarias e Veterinarias, Universidade Estadual Paulista (FCAV/UNESP) in Jaboticabal, SP, and also in a commercial orchard in Araguari, MG, with the objective to verify the potential of vegetative growth (stem diameter, height of plants and leaf number) of plants of passion fruit (Passiflora alata Dryander), gotten by cutting and seed, comparing the initial development of plants in the field. This experiment was carried out from January 2002 to February 2003. The experiment using seeds was conducted at a shadow house, and the one that used cuttings in an intermitent mist. The cuttings and seeds were collected from adult plants which came from Passifloraceae Active Germoplasm Bank (BAG) of the Plant Production Department of FCAC/UNESP. For the cuttings, it was used the intermediate part of the branches in stadium of vegetative growth. The seeds, in order to obtain the seedlings, had been sown in plastic trays. Cuttings and seedlings were transplanted to plastic bags with substrate in shadow house and with daily irrigation. They were acclimatized and planted on field, after 60 days. on field, the stem diameter, plant height and number of leaves were better for cuttings than for seedlings in Jaboticabal, SP. In Araguari, MG, stem diameter was larger in the seedlings, which plant heights and number of leaves were larger on cuttings.

Genetic associations between flight speed and growth traits in Nellore cattle

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

Evaluation of corn cultivars harvested at two cutting heights for ensilage

Objetivou-se neste estudo avaliar as características agronômicas, a composição químico-bromatológica e a digestibilidade de 11 cultivares de milho (Zea mays) colhido em duas alturas de corte. As cultivares D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, CO 9621 e BR 205 foram avaliadas quando colhidas 5 cm acima do solo (baixa) e 5 cm abaixo da inserção da primeira espiga (alta). O experimento foi delineado como blocos casualizados, com três repetições, arranjados em esquema fatorial 11 x 2. Os cultivares apresentaram produções semelhantes de matéria seca de forragem e de grãos. As porcentagens das frações colmo, folha, palha, sabugo e grão diferiram entre os cultivares, assim como os teores de matéria seca da planta inteira no momento da colheita. Considerando a planta inteira, apenas os teores de energia bruta, nitrogênio da fração fibra em detergente neutro e a digestibilidade in vitro da fibra em detergente neutro e detergente ácido não diferiram entre os cultivares. O aumento da altura de corte melhorou a qualidade da forragem, devido à redução das frações colmo e folha e dos teores dos constituintes da parede celular.

Production of polysaccharidases in different carbon sources by Leucoagaricus gongylophorus Moller (Singer), the symbiotic fungus of the leaf-cutting ant Atta sexdens linnaeus

Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens, produces polysaccharidases that degrade leaf components by generating nutrients believed to be essential for ant nutrition. We evaluated pectinase, amylase, xylanase, and cellulase production by L. gongylophorus in laboratory cultures and found that polysaccharidases are produced during fungal growth on pectin, starch, cellulose, xylan, or glucose but not cellulase, whose production is inhibited during fungal growth on xylan. Pectin was the carbon source that best stimulated the production of enzymes, which showed that pectinase had the highest production activity of all of the carbon sources tested, indicating that the presence of pectin and the production of pectinase are key features for symbiotic nutrition on plant material. During growth on starch and cellulose, polysaccharidase production level was intermediate, although during growth on xylan and glucose, enzyme production was very low. We propose a possible profile of polysaccharide degradation inside the nest, where the fungus is cultured on the foliar substrate.

Evaluation of the adequacy of diflubenzuron and dechlorane in toxic baits for leaf-cutting ants (Hymenoptera : Formicidae) based on formicidal activity

Studies assessing the characteristics of active ingredients (AIs) of toxic baits for leaf-cutting ants are still scarce, although the need for a delayed action of these compounds on adult workers has been well accepted (mortality <= 15% at 24 h and <= 90% at 21 days). Therefore, we determined the insecticidal action of two AIs used in commercial baits, diflubenzuron and dechlorane, over time in workers, and discussed the control of colonies in relation to the existing literature. Dechlorane presented excellent insecticidal activity with a delayed action at all concentrations tested, although its commercial use has been prohibited due to its organochlorine nature. In contrast, diflubenzuron did not cause significant mortality or symptoms of intoxication, indicating that the successful cases reported with the use of baits containing this AI were in fact due to an accidental contamination with dechlorane. We comment about the ineffectiveness of diflubenzuron on alternative targets, i.e., young forms and the mutualistic fungus, supporting the concept that the AI needs to a have a delayed action on adult workers.

Larval isolation and brood care in Acromyrmex leaf-cutting ants

The larvae of leaf-cutting ants are maintained within the fungus gardens of their colonies and are fed pieces of fungus by the adult workers. However, little else is known about the nature of the worker-larva interaction in these ecologically important ants. To examine whether workers can gauge the needs of individual larvae, we isolated larvae without adult workers for different lengths of time. We then placed workers with the larvae and recorded the type and frequency of the subsequent behaviours of the workers. Workers scraped the mouthparts of larvae, ingested their faecal fluid, fed them with fungal hyphae, transported them around the fungus garden and, most frequently, licked their bodies. The workers were also observed to 'plant' fungal hyphae on the bodies of larvae. Workers interacted more frequently with larvae that had been isolated without workers than with those that had not, but there was no effect of the length of isolation. The results suggest that the interactions are complex, involving a number of behaviours that probably serve different functions, and that workers are to some extent able to assess the individual needs of larvae.

Filamentous fungi found on foundress queens of leaf-cutting ants (Hymenoptera: Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Geographic Distribution and Population Estimate of Leaf-cutting Ants of the Genus Acromyrmex (Hymenoptera: Formicidae) in Southwestern Bahia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Growth of the Symbiotic Fungus of the Grass-cutting Ant Atta capiguara (Hymenoptera: Formicidae): Effect of Grass Extracts

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

Selectivity of Workers of the Grass-Cutting Ants Atta bisphaerica and Atta capiguara (Hymenoptera: Formicidae) to Vegetable Oils

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

Digging effort in leaf-cutting ant queens (Atta sexdens rubropilosa) and its effects on survival and colony growth during the claustral phase

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

Estudo térmico e de materiais na construção de casas populares com blocos confeccionados a partir de um composto a base de cimento, gesso, eps e raspa de pneu

We built an experimental house on an UFRN´s land using blocks made by a composite consisting of cement, plaster, EPS, crushed rubber and sand. Several blocks were made from various compositions and we made preliminary tests of mechanical and thermal resistance, choosing the most appropriate proportion. PET bottles were used inside the block to provide thermal resistance. In this work, a second function was given to the bottles: to serve as a docking between the blocks, because the ends of the cylinders came out of each block on top as well as at the bottom, with the bottom cut, allowing to fit of the extremities of the upper cylinder of a block in the lower holes of the other one, which were formed by the cutting already mentioned. Minimum compression tests were performed according to ABNT standards for walls closing blocks (fence). With that house built, we did studies of thermal performance in order to ascertain conditions of comfort, checking external and internal temperatures in the walls and in the ambient, among other variables, such as wind speed and relative humidity. The resulting blocks provided adequate thermal insulation to the environment, where the walls presented differences up to 11.7 ºC between the outer and inner faces, getting the maximum temperature inside the house around 31 °C, within the so-called thermal comfort zone for warm climates. At the end of the experiments it was evident the effectiveness of that construction in order to provide thermal comfort in the internal environment of the house, as well as we could confirm the viability of building houses from recyclable materials, reducing the constructive costs, becoming a suitable alternative for low- incoming families. Moreover, besides the low cost, the proposal represents an alternative use of various recyclable materials, therefore considered an ecological solution

Nest Digging by Leaf-Cutting Ants: Effect of Group Size and Functional Structures.

Leaf-cutting ant workers dig underground chambers, for housing their symbiotic fungus, interconnected by a vast quantity of tunnels whose function is to permit the entrance of food (leaves), gaseous exchanges, andmovement of workers, offspring, and the queen. Digging is a task executed by a group of workers, but little is known about the group effect and group-constructed functional structures. Thus, we analyzed the structures formed by worker groups (5, 10, 20, and 40 individuals) of the leaf-cutting ant, Atta sexdens rubropilosa, for 2 days of excavation. The digging arena was the same for the 4 groups, with each group corresponding to a different density. Our results verified a pattern of tunneling by the workers, but no chamber was constructed. The group effect is well known, since the 40-worker group dug significantly more than the groups of 5, 10, and 20. These groups did not differ statistically from each other. Analysis of load/worker verified that workers of the smallest group carried the greatest load. Our paper demonstrates the group effect on the digging of nests, namely, that excavation is proportional to group size, but without emergence of a functional structure such as a chamber.

An Intelligent System for Petroleum Well Drilling Cutting Analysis

Cutting analysis is a important and crucial task task to detect and prevent problems during the petroleum well drilling process. Several studies have been developed for drilling inspection, but none of them takes care about analysing the generated cutting at the vibrating shale shakers. Here we proposed a system to analyse the cutting's concentration at the vibrating shale shakers, which can indicate problems during the petroleum well drilling process, such that the collapse of the well borehole walls. Cutting's images are acquired and sent to the data analysis module, which has as the main goal to extract features and to classify frames according to one of three previously classes of cutting's volume. A collection of supervised classifiers were applied in order to allow comparisons about their accuracy and efficiency. We used the Optimum-Path Forest (OPF), Artificial Neural Network using Multi layer Perceptrons (ANN-MLP), Support Vector Machines (SVM) and a Bayesian Classifier (BC) for this task. The first one outperformed all the remaining classifiers. Recall that we are also the first to introduce the OPF classifier in this field of knowledge. Very good results show the robustness of the proposed system, which can be also integrated with other commonly system (Mud-Logging) in order to improve the last one's efficiency.