Why do the ithomiines (Lepidoptera, Nymphalidae) aggregate? Notes on a butterfly pocket in central Brazil

This study provides information on the species composition and the number of butterflies in different phases of an ithomiine aggregation during the 2004 dry season in central Brazil, and tests some hypotheses concerning the pocket formation. The results obtained suggest that ithomiine pockets constitute primarily an adaptation of butterflies to the adverse climatic conditions of the dry season, such as high temperatures and low air relative humidity, rather than the occurrence of large concentrations of adult food resources (flowers visited for nectar were not found in the pocket site) or defense against visually hunting predators (contrary to the prediction tested, the frequency of butterflies bearing birds beak marks on the wings significantly increased along the period of pocket formation, especially in the case of Mechanitis polymnia, the most abundant species in the pocket). Other hypotheses concerning the pocket formation are also discussed.

Seasonal flight and resource collection patterns of colonies of the stingless bee Melipona bicolor schencki Gribodo (Apidae, Meliponini) in an Araucaria forest area in southern Brazil

Melipona bicolor schencki occurs in southern Brazil and at high elevations in southeastern Brazil. It has potential for use in meliponiculture but this stingless bee species is vulnerable to extinction and we have little knowledge about its ecology. In order to gather essential information for species conservation and management, we made a study of seasonal flight activities in its natural environment. We sampled bees entering the nests with pollen, nectar/water and resin/mud, in five colonies during each season. In parallel, we analyzed the influence of hour of the day and meteorological factors on flight activity. Flights were most intense during spring and summer, with daily mean estimates of 2,100 and 2,333 flights respectively, while in fall and winter the daily flight estimate was reduced to 612 and 1,104 flights, respectively. Nectar and water were the most frequently-collected resources, followed by pollen and building materials. This preference occurred in all seasons, but with variations in intensity. During spring, daily flight activity lasted over 14 hours; this period was reduced in the other seasons, reaching eight hours in winter. Meteorological factors were associated with 40.2% of the variation in flight and resource collection activity. Apparently, other factors that we did not measure, such as colony needs and availability of floral resources, also strongly influence the intensity of resource collection.

First record of the behavior of latex drainage by Trigona spinipes (Fabricius) (Hymenoptera, Apidae) in laticiferous flowers

This paper describes the behavior of the bee Trigona spinipes, to avoid the latex, when piercing the base of the tubular corolla of the flowers of Mandevilla guanabarica in order to steal the nectar.

Fusarium wilt incidence and common bean yield according to the preceding crop and the soil tillage system

The objective of this work was to evaluate the effects of preceding crops and tillage systems on the incidence of Fusarium wilt (Fusarium oxysporum f. sp. phaseoli) and common bean (Phaseolus vulgaris) yield. The cultivar BRS Valente was cultivated under center‑pivot irrigation in the winter seasons of 2003, 2004 and 2005, after several preceding crops established in the summer seasons. Preceding crops included the legumes Cajanus cajan (pigeon pea), Stylosanthes guianensis, and Crotalaria spectabilis; the grasses Pennisetum glaucum (millet), Sorghum bicolor (forage sorghum), Panicum maximum, and Urochloa brizantha; and a consortium of maize (Zea mays) and U. brizantha (Santa Fé system). Experiments followed a strip‑plot design, with four replicates. Fusarium wilt incidence was higher in the no‑tillage system. Higher disease incidences corresponded to lower bean yields in 2003 and 2004. Previous summer cropping with U. brizantha, U. brizantha + maize consortium, and millet showed the lowest disease incidence. Therefore, the choice of preceding crops must be taken into account for managing Fusarium wilt on irrigated common bean crops in the Brazilian Cerrado.

Toxicity of organic farming‑compatible products to the coffee leaf miner

The objective of this work was to evaluate the toxicity of organic farming‑compatible products to the coffee leaf miner Leucoptera coffeella. Lime sulphur, enriched Bordeaux mixture (Viça Café Plus), and the "supermagro" biofertilizer were first tested in laboratory. The most promising product was tested afterwards under field conditions. In laboratory, different concentrations of each product were applied on L. coffeella eggs and on infested coffee‑mined leaves. Only lime sulphur had ovicidal effects at an acceptable concentration (1.6%) for field applications, but no significant effect on larvae mortality was found. Enriched Bordeaux mixture and the "supermagro" biofertilizer had no effect on L. coffeella eggs and larvae. In the field trial, biweekly or monthly sprayings of lime sulphur at different concentrations caused population decrease after 30 days; however, this effect was not significant after 60 or 90 days.

Passiflora edulis Sims: the correct taxonomic way to cite the yellow passion fruit (and of others colors)

Passiflora edulis, the passion fruit native from Brazil, has several common names (such as sour passion fruit, yellow passion fruit, black passion fruit, and purple passion fruit), and presents a wide variability with the different rind colors of its fruits, which are very easy to notice. However, in 1932, Otto Degener suggested that the yellow passion fruit had its origin in Australia through breeding, calling it P. edulis forma flavicarpa, and that it could be distinguished by the color of the fruit, the deeper shade of purple of the corona, and the presence of glands on the sepals. These distinctions do not support themselves, for the glands are common to the species (although they may be absent), and the corona has a wide range of colors, regardless of the color of the fruit. A more critical ingredient is the fact that the external coloration of the fruit is a character of complex inheritance and is not dominant, thus displaying a number of intermediate colors, making it difficult to identify the extreme colors. For the correct scientific naming of agricultural plants, the International Code of Botanical Nomenclature must be used in conjunction with the International Code of Nomenclature for Cultivated Plants, with the selections with significant agronomic characteristics recognized and named cultivars. In accordance with the international convention promoted by the UPOV, of which Brazil is a signatory, several colors (light yellow, yellow, orange yellow, pink red, red, red purple, green purple, purple, and dark purple) can be recognized in order to adequately characterize passion fruit cultivars within the species P. edulis. At taxonomic level, Passiflora edulis Sims must be used for any plant and color of sour passion fruits, in combination with a cultivar name for the selected materials.

Topworking of 'Bengal' lychee trees in the state of São Paulo, Brazil

This study aimed to evaluate the performance of 'Feizixiao', 'Nuomici', 'Heiye', 'Kway May Pink' and 'Bengal' lychee cultivars topworked onto bearing 'Bengal' trees. The experiments were carried out in commercial orchard at Rio das Pedras Farm in Jundiaí, state of São Paulo. The experimental design consisted of randomized blocks in a subdivided parcel arrangement, in which the parcel consisted of five cultivars and the sub-parcel consisted of six evaluation periods. Five replicates of three plants per parcel and six grafts per plant, (with two grafts per main branch) were used. The trees were approximately 10 years old propagated by air layering and planted with 6 x 4 m (416 plants/ha) spacing. The following characteristics were evaluated: success rate of the grafts, number of shoots, shoot length, number of nodes, number of leaves and chlorophyll content (SPAD). The control ('Bengal'/'Bengal') had the highest grafting success rate with 89.9%. On the other hand, 'Heiye', 'Feizixião', 'Nuomici' and 'Kway May Pink' had, respectively, 60.6, 55.0, 52.6 and 47.0% grafting success rates. All of the shoot grafts had normal growth with no signs of incompatibility. Therefore, the cultivars studied are compatible with 'Bengal' and may be used on commercial orchards.

Aplicação da cromatografia por exclusão e da cromatografia gasosa de alta resolução na análise do café

The combination of high performance exclusion chromatography (HPEC) and gas chromatography (GC) was applied to the analysis of six coffee samples that were previously characterized by sensory tests as of good or poor quality. The data obtained by the two techniques were statistically evaluated by "Principal Components Analysis" (PCA) using selected peak areas. The results showed the potential of the described techniques for coffee analysis. The HPEC technique monitored with the U.V. detector at 272 nm and followed by PCA may be correlated with sensorial data, particularly if a wider group of samples is used.

Componentes voláteis do café torrado. Parte I: compostos heterocíclicos

A review of heterocyclic compounds in roasted coffee is presented. The contents, precursors and sensorial properties of furans, pyrroles, oxazoles, thiazoles, thiophenes, pyrazines and pyridines are discussed. The impact heterocyclic compounds of coffee aroma are described.

Componentes voláteis do café torrado. Parte II. Compostos alifáticos, alicíclicos e aromáticos

This review is about the aliphatic, alicyclic and aromatic compounds (non-heterocyclic compounds) that are present in the volatile fractions of roasted coffees. Herein, the contents, aroma precursors and the sensorial properties of volatile phenols, aldehydes, ketones, alcohols, ethers, hydrocarbons, carboxylic acids, anhydrides, esters, lactones, amines and sulphur compounds are discussed. Special attention is given to the compounds of these groups that are actually important to the final aroma of roasted coffees.

Determinação de compostos bioativos em amostras comerciais de café torrado

Coffee is a product consumed all around the world, Brazil being the biggest exporter. However, little is known about the difference in composition of the different brands in terms of bioactive substances. In the present study, ten of the most consumed brands of coffee in Rio de Janeiro were analyzed. Caffeine contents, trigonelline and total chlorogenic acid varied from 0.8 g/100g to 1.4 g/100g; 0.2 g/100g to 0.5 g/100g and from 3.5 g kg-1 to 15.9 g kg-1, respectively. The large heterogeneity observed in the amounts of the bioactive compounds can be attributed to different formulations of the various brands, as well as to different roasting conditions.

Metodologia para análise simultânea de ácido nicotínico, trigonelina, ácido clorogênico e cafeína em café torrado por cromatografia líquida de alta eficiência

A reverse phase liquid chromatography method was developed for simultaneous determination of trigonelline, caffeine, nicotinic and chlorogenic (5-CQA) acids in roasted coffee. A gradient of acetic acid/acetonitrile was used as mobile phase and detection was carried out in the UV. The samples were extracted with acetonitrile/water (5:95 v/v) at 80 ºC/10 min. Good recovery (89 to 104%), repeatability and linearity were obtained. Detection limits of 0.01, 0.15, 0.04 and 0.04 mg mL-1 were observed for nicotinic acid, trigonelline, 5-CQA and caffeine. The method, applied to arabica and robusta coffees with different degrees of roasting, was efficient and fast (~35 min) and also allowed identification of cinnamic acids.

Determinação de açúcar total em café cru por espectroscopia no infravermelho próximo e regressão por mínimos quadrados parciais

In this work a fast method for the determination of the total sugar levels in samples of raw coffee was developed using the near infrared spectroscopy technique and multivariate regression. The sugar levels were initially obtained using gravimety as the reference method. Later on, the regression models were built from the near infrared spectra of the coffee samples. The original spectra were pre-treated according to the Kubelka-Munk transformation and multiplicative signal correction. The proposed analytical method made possible the direct determination of the total sugar levels in the samples with an error lower by 8% with respect to the conventional methodology.

Influência do processamento e da torrefação sobre a atividade antioxidante do café (Coffea arabica)

The aim of this work is to evaluate the influence of processing (semi-dry and dry) and roasting (light, medium and dark) on the antioxidant activity of coffee brews, using tests to determine the reducing power and the DPPH scavenging, Fe+2 chelating and lipid peroxidation inhibition activities. All of the coffee brews presented concentration-dependent antioxidant activity. The light coffee samples presented the higher reducing power and DPPH scavenging activity. Its ion chelating capacity was similar to the medium samples, but was less than the green coffee chelating capacity. The semi-dry processing was more efficient than the dry processing only for the reducing power. All of the samples presented high lipid peroxidation inhibition activity. Based on the results the degree of coffee roasting seems to be more important than the processing to determine the antioxidant activity of brews.

Utilização do índice de retenção linear para caracterização de compostos voláteis em café solúvel utilizando GC-MS e coluna HP-Innowax

Gas chromatography coupled with mass spectrometry (GC-MS) is widely used for the characterization of volatile compounds. However, due to the complexity of the soluble coffee matrix, a complete identification of the components should not be based on mass spectra interpretation only. The linear index of retention (LRI) is frequently used to give support to mass spectra. The aim of this work is to investigate the characterization of the volatile compounds in soluble coffee samples by GC-MS using LRI values found with a HP-INNOWAX column. The method used allows a significant increase of the reliability of identifying compounds.