Ant fauna (Hymenoptera: Formicidae) in Magnoliophyta native to the Atlantic forest

The aim of the study was to analyze the preferences of ant species visiting the trunks of eight species of Magnoliophyta, belonging to the families Fabaceae, Arecaceae, Myrtaceae, Melastomataceae and Euphorbiaceae, located in a fragment of the Atlantic Forest in southeastern Brazil. A total of 101 ant species, belonging to eight subfamilies and 32 genera, were sampled during the 12-month collection period. Close to 30% of the ant species can be considered arboreal, and the others are species that nest in the ground and use trees only for foraging, which can be occasional, as in the case of the Ecitoninae sampled in Arecaceae and Euphorbiaceae. Pachycondyla mesonotalis was the only species collected on all the Magnoliophyta, whereas Camponotus rufipes, Acromyrmex niger and Crematogaster spp., were found on 87.5% of the trees analyzed. No strong similarities were found, using the Jaccard Index, among plant species in the same family of Magnoliophyta based on the visiting ants, except for the Euphorbiaceae species. This result is probably related to the presence of extra-floral nectar, which is very attractive to ants and characteristic of this family.

Attractiveness of citrus pulp and orange albedo extracts to Atta sexdens rubropilosa (Hymenoptera: Formicidae)

The present study aimed to compare the attractiveness of industrial citrus pulp with the handmade orange albedo to the workers of Atta sexdens rubropilosa. For this, filter paper fragments were impregnated with organic extracts obtained through chemical extraction and sequential fractioning with hexane and dichloromethane and offered to different field nests. It was verified that the industrial citrus pulp extract is as good as the handmade orange albedo extract. This preference is discussed keeping in mind the chemical, behavioral and nutritional factors.

Lipids in oocytes of ants Neoponera villosa (Hymenoptera: Ponerinae)

Elements of oocyte of Neoponera villosa ants (workers and queen) were analyzed histochemically and ultrastructurally. It was observed that lipids are the first element to be deposited. They appear in oocytes of all stages. Lipids probably arose in the younger oocytes (stages I and II) from mitochondria of their own cytoplasm and from the nurse cells as well. In mature oocytes (stage III) the cells of the follicular epithelium appears with droplets of lipids in their cytoplasm showing that besides the other sites, this epithelium can also be active in lipid synthesis.

Morphohistochemical characterization of the perivisceral fat body in royal and worker female castes in different ages of Atta sexdens rubropilosa ants (Hymenoptera, Formicidae)

The morphohistochemical study of the fat body in royal and worker castes of Atta sexdens rubropilosa revealed that this tissue is made up of trophocytes and oenocytes, trophocytes being the cells with cytoplasmic inclusions and irregular nuclei and the oenocytes cells with homogeneous cytoplasm and rounded nuclei. The trophocytes of queens presented many lipidic and proteic granules, while those of workers presented trophocytes with fine granulation in the cytoplasm constituted mainly by lipids and carbohydrates. The oenocytes from the worker caste of A. s. rubropilosa presented cytoplasm filled mainly with lipoproteic material.

The mesosomal gland of Xylocopa frontalis (Hymenoptera, Apidae, Xylocopini)

Males of Xylocopa fimbriata and X. micans present mesosomal glands that produce secretions containing many volatile substances with an intense floral fragrance, which resembles the fragrance produced by flowers that are attractive to the females of both species. The mating territories occupied by males of X. frontalis have no helpful resources for the females of this species, which are probably attracted to these environments by sexual pheromone(s) produced in the male mesosomal glands (lek polygyny). In this work, the presence of these glands in males of X. frontalis was confirmed and their anatomy and ultrastructure were described. An attempt to correlate the morphological characteristics of the mesosomal glands with the male territorial behavior was also carried out.

Toxicity of Azadirachta indica to leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae)

The leaf-cutting ants are responsible for great economical damages in cultivated areas, and because of this characteristic, they have aroused the interest of researchers around the world. Thus, extracts of neem (Azadirachta indica, A. Juss) were tested through ingestion and contact experiments to investigate their toxicity to Atta sexdens rubropilosa workers. Crude extract of neem seed oil was toxic to the ants by ingestion in all concentrations tested but no toxicity was observed in contact experiments. However, crude extract of neem seed paste produced a significant toxicity to workers by ingestion and by contact.

Influence of the collection methodology on the Apis mellifera venom composition: Peptide analysis

Differences of venom peptide composition as function of two collection methodologies, electrical stimulation (ES) and reservoir disruption (RD), were analyzed by reverse-phase HPLC in Apis mellifera races - A. m. adansonii, A. m. ligustica and Africanized honeybee. The analyses were performed through determination of the relative number and percentage of each molecular form associated to the peaks eluted by chromatography. Comparison of these profiles revealed qualitative and quantitative differences related to the venom collection methodology as well to the three races analyzed. In contrast to data usually found for venom proteins, the three races presented a major number of peaks or molecular forms when venom was collected by ES. Besides, in general, the relative concentration of each peak was higher for ES in relation to RD. That indicates the presence of molecular precursors in the venom obtained by RD. The presence/absence pattern of the peaks, such as their relative concentrations showed a closer similarity between A. m. adansonii and the Africanized honeybees than that observed between these and A. m. ligustica. The obtained data allowed a discussion about the differences in the relative concentration of each venom component according to the collection methodology, and finally the biological action of the venom in different races. So, these results, apart from being useful to establish a peptide profile for each bee race as a function of the venom collection methodology, pointed out once more that the chromatographic techniques are a great tool for the identification of A. mellifera subspecies.

Toxicity of straight-chain fatty acids to leaf-cutting ants Atta sexdens rubropilosa (Hymenoptera: Formicidae) and the symbiotic fungus Leucoagaricus gongylophorus

This work determined toxicity and attractiveness of straight-chain fatty acids (C 5 to C 12) to Atta sexdens rubropilosa (Forel) workers. The effect to the symbiotic fungus, Leucoagaricus gongylophorus (Singer) Möller, was also tested with the fatty acids C 6 to C 12. A strong mortality of leaf-cutting ants that were fed with an artificial diet containing fatty acids C to C at concentrations above 1.0 mg.ml -1 was observed. Rice flakes impregnated with solutions of these fatty acids were repellent to leaf-cutting ants. Contact experiments showed that treatments with C 6 and C 7 at concentration of 100 mg.ml -1 significantly reduced the survival rate of leaf-cutting ants. The fatty acids C 8 to C 11 were toxic to leaf-cutting ants when topically tested at concentration of 200 mg.ml -1. In relation to the fungus' bioassays, the fatty acids C 6 to C 12 at concentration of 0.1 mg.ml -1 inhibited 100% of the fungal development. Although when the concentration was reduced by half no inhibition effects were observed. The results showed that straight-chain fatty acids have desirable properties for controlling leaf-cutting ants since they directly interfere with both organisms of the symbiotic relationship. The potential of fatty acids as well as ways to control leaf-cutting ants with these compounds are discussed in this article.

Bionomics and identification of Acromyrmex (Hymenoptera: Formicidae) through an illustrated key

This study is based on sampled data obtained in 60 equally distant municipalities of São Paulo State. In this study, we proposed a tool to identify Acromyrmex species in a practical and agile manner through the use of an illustrated key that demonstrates the morphological attributes of workers, associated with the type of cut plant material, external and internal appearance of nests and nidification sites. Through sampling, eleven species and six subspecies of Acromyrmex occurring in the State were identified, including the first registers of A. diasi and A. subterraneus molestans.

Male behavior of Mischocyttarus cerberus (Hymenoptera, Vespidae) during attacks on the nest by ants

The objectives of the present study were to verify if the males of the wasp Mischocyttarus cerberus participate in defense of the nest as they react to attack by ants, and to observe if they use chemical defense. First, wasps were stimulated with an empty pair of tweezers and a second stimulation was done with a pair of tweezers containing an ant, Camponotus crassus. The behaviors of the wasps were recorded and analyzed. The males can participate in defense of the nest, presenting some aggressive behaviors, even so, most of the time they ignore the stimulation, hide behind the nest and stay immobile.

The role of workers in transferring queen substances and the differences between worker castes in the leaf-cutting ant, Acromyrmex subterraneus brunneus (Hymenoptera: Formicidae)

The present study focused on the relationship between the queen and workers in Acromyrmex subterraneus brunneus colonies mediated by the possible transfer of substances from the fertile to the sterile caste. The queens were submitted to different situations of physical limitation, i.e., they were kept isolated in cages with holes that only permitted the entry of workers but left the queen isolated. A tracer (water-soluble dye) was applied to the pronotum and gaster of the queen and its dispersal among workers was analyzed. The results demonstrated that the minor sub caste (0.7-0.9 mm) passed on the dye through allogrooming and self-grooming, or transferred the dye through trophallaxis to the major sub caste (1.2-2.0 mm) when they were not in direct contact with the queen. These findings indicate the communication and probable transfer of substances from the queen to the workers, as well as a substance transfer between workers.

Interspecific interactions between Coptotermes gestroi and Heterotermes tenuis (Isoptera: Rhinotermitidae) under laboratory conditions

Coptotermes gestroi and Heterotermes tenuis are termite pests. Both species have cryptic habits, and are known as subterranean termites. The aim of this study was to verify if food availability and alterations in the proportion of soldiers interfere in the interactions between these termites, since the introduced species C. gestroi occupies the same niche as the native species H. tenuis. Different bioassays were conducted in order to evaluate these interspecific interactions. The results showed that C. gestroi presented advantages in the occupation of territory in all bioassays and suggest a higher efficiency of this species in the search for alternative food sources, especially when the number of soldiers was higher than that of H. tenuis. Additionally, it is possible to conclude that food availability and the different proportion of soldiers involved in the interspecific confrontations interfere in the occupation of territory and in the agonistic behavior between these two species of termites.

Brood care and male behavior in queenless Acromyrmex subterraneus brunneus (Hymenoptera: Formicidae) colonies under laboratory conditions

In this study we describe and quantify the brood care performed by workers in queenless colonies of the leaf-cutting ant Acromyrmex subterraneus brunneus. Fifteen behavioral acts were recorded in the three colonies studied. The behavioral repertoire of males was more limited, with only four behavioral acts being observed: feeding through workers, collecting staphylae and self-feeding, mutual grooming between adults (worker-males), and self-grooming. Males were also found to be able to collect food (staphylae or fungal hyphae) from the fungus garden and to feed themselves, not requiring workers for this activity. This study contributes to a better understanding of the basic biology of leaf-cutting ant colonies, with the description and quantification of the activities performed by the members of a colony in a situation of the loss of the fertile caste.

Determinação da distribuição de um nível de turbidito na formação Macaé no campo de Namorado através de uso de atributos sísmicos

This study was developed on the basis of petrophysics characterization, 3D seismic interpretation, and rock-wire-log integration. The results were integrated with amplitude attribute through cross plot (rock attribute x amplitude value). 3D seismic data also allowed inteipreting the top of Lagoa Feia, Macaé, and Carapebus formations, and Outeiro Member. The analyses of the maps of structures and attributes, integrated with wire-log data, suggest that Namorado turbidite level is candidate to be mapped with stratigraphic attributes like AverageTroughAmplitude, RMS velocity and Total AbsoluteAmplitude. Lagoa Feia Formation attribute maps (Dip-Azimuth and TotalEnergy) allows to interpret a low fault density at the carbonate coquina level in the Namorado field. This level is also considered one at the best seismic reflector and an important reservoir of the Campos Basin.

Sucessão sedimentar do Grupo Bauru na região de Pirapozinho (SP)

There is yet enthusiastic debate in the literature about the environmental conditions that originated the Cretaceous deposits of the Bauru Group, despite many authors accept that arid climatic conditions widely dominant at the base, evolved to chiefly fluvial-lacustrine conditions at the intermediate portion, and to arid conditions again at the top of the unit. The Bauru Group covers an area of about 117.000 km 2 of the Paraná Basin in São Paulo State territory. Core samples of this lithostratigraphic unit collected from a drill hole at Pirapozinho (Southwest of the São Paulo State) are described and together with well log data brought new information that do not agree with the described model. It was identified in this well the Caiuá, Pirapozinho, Santo Anastácio, Araçatuba and Adamantina formations. The study of these core samples clearly showed the dominance of hydrodynamic sedimentary structures and high to medium intensity of bioturbation in whole profile. These characteristics observed in core samples and compared to patterns of geophysical logs testify the dominance of fluvial processes in the Bauru Group deposition at the studied area. These new data suggests that the paleo-environmental evolution of the unit was much more complex, showing strong lateral and vertical changes that diverges from the model more widely accepted in the literature.