Variability of non-mutualistic filamentous fungi associated with Atta sexdens rubropilosa nests

A survey of the filamentous fungi other than the symbiotic one found in association with Atta sexdens rubropilosa colonies was carried out. Different fungal species (27 taxa) were isolated a few days after treating the workers with toxic baits (sulfluramid; Mirex-SO), from 40 laboratory and 20 field nests. Syncephalastrum racemosum (54 %) and Escovopsis weberi (21 %), Trichoderma harzianum (38 %) and Fusarium oxysporum (23 %) were the prevalent species in laboratory and field nests, respectively. Acremonium kiliense, Acremonium strictum, E. weberi, F oxisporum, Fusarium solani, Moniliella silaveolens and T harzianum were found in both nests' groups. We revealed that many filamentous fungi can co-exist in a dormant state inside the nests of these insects and some of them appear to be tightly associated with this environment.

A SIMPLE METHOD FOR DETERMINING LOCATION OF FORAGING ANT NESTS USING LEAF-CUTTING ANTS AS A MODEL

In many situations, it is difficult to evaluate the location of nests of ants, especially in tropical systems, or to determine which trail system corresponds with which nest, as in the case of high-density populations of leaf-cutting ants, Atta spp. Fragments of colored drinking straws coated with an attractant, generally vegetable oil and/or a starchy carbohydrate, are carried by ants and following removal of the attractant are deposited in middens, allowing determination of the origin of foraging workers.

AN INEXPENSIVE METHOD FOR CHROMOSOME PREPARATIONS FROM FEATHER PULP IN BIRDS, USING SHORT-TERM TREATMENT WITH COLCHICINE IN-VITRO, DEMONSTRATED ON AMAZONA-AMAZONICA (PSITTACIDAE)

In order to develop an efficient and low-cost technique for obtaining bird chromosome preparations, and to adapt the cytogenetic process of bird sexing for general use at zoos and breeding farms with the technical support of cytogenetics laboratories, we tested variants of the technique described by Giannoni et al. (Genet. Sel. Evol. 23: 123-125, 1991), based on the utilization of cellular material from growing feather pulp cultured in complete medium for six hours. Hanks' saline solution gave satisfactory performance as a substitute for complete medium, with no need to use PHA, serum of collagenase, when utilized in material obtained from feather pulp of Amazona amazonica (Psittacidae).

Interspecies variation in orbital bone structure of psittaciform birds (with emphasis on Psittacidae)

Objectives: This text presents an anatomical study of the normal bony orbital structure of a sample of different bird species belonging to the order Psittaciformes.Procedures: the bony anatomy of Psittaciformes' skulls was examined and described using cadavers of birds that were presented already dead to the Federal University of Parana, Brazil or had been euthanized for humane reasons. Dissections of the orbital cavity were performed under 2-4 x magnification, and descriptions of the orbital bones were made from observations of macerated skulls that had been boiled and cleaned. The present paper discusses the main features of the bony orbit of psittaciform birds, describing known anatomical information but also bringing new information, mainly concerning species differences that might help not only veterinary anatomists but also zoologists, clinicians, researchers, and students of veterinary ophthalmology to better comprehend this order of birds.Results and conclusions: Variations in the anatomic conformation of the bony elements of the orbit were observed in different species of Psittaciformes. Based on these differences, Psittaciformes were classified into two different groups. The first group of Psittaciformes shows an enclosed (complete) bony orbit formed by the junction of the orbital with the postorbital processes, creating a suborbital arch. The second group of Psittaciformes essentially lacked a suborbital arch, presenting an open (incomplete) bony orbit, typical of most modern birds. In the latter group, orbital and postorbital processes are present.

Nests and nesting sites of Brazilian forest rodents (Nectomys squamipes and Oryzomys intermedius) as revealed by a spool-and-line device

Patterns of nest construction and nest site selection of two murid rodents of the Brazilian Atlantic rainforest were described. The animals were captured in an area of about 1.5 ha of primary forest, marked, equipped with a spool-and-line device and released at the capture point. The next day we followed the thread to find their nests. In total 11 nests of Nectomys squamipes (Brants, 1827) and 13 of Oryzomys intermedius (Leche, 1886) were found. They were all egg-shaped, about 15 cm long and 10 cm wide, without any apparent entrance and consisted of dry leaves and grass. The two species differed in the selection of nest sites. The nests of N. squamipes were close to streams and built inside decomposed fallen logs or using natural entrances between the soil and tangled roots or rocky crevices. Nests of O. intermedius were built under or inside fallen logs and inside aerial root systems of palms. The spool-and-line technique used here is useful to provide detailed information on several aspects of the ecology and natural history of small mammals.

Utilization of epiphytes by birds in a Brazilian Atlantic Forest

Epiphytes constitute a great part of the vegetation biomass in Neotropical forests, offering a large variety of resources to birds. Despite their structural and ecological importance, few studies investigated the use of epiphytes by birds in the Neotropical region. We studied the bird species that exploit vascular epiphytes (and hemi-epiphytes) in an Atlantic forest site in southeastern Brazil. The resources exploited, seasonal variation in the use of epiphytes, the frequency of foraging and selectivity in epiphytes, and the relationship between the use of epiphytes and the participation in mixed-species bird flocks were investigated. After 360 h of observations along trails crossing the forest, 24 bird species (12 families) were recorded in a total of 74 events of epiphyte exploitation. Thamnophilidae (four species), Trochiliclae, Thraupidae and Furnariidae (three species) were the richest bird families in our sample, while Furnariidae and Dendrocolaptidae were the more frequently recorded families. Plants in the Bromeliaceae and Araceae families were the most abundant and more frequently exploited epiphytes. Nectar, water, nest material and invertebrates were the most frequently exploited resources, mainly from Bromeliaceae. None of the species for which we had enough data revealed to be a frequent user of epiphytes for foraging or selective to any epiphyte group. The White-eyed Foliage-gleaner (Automolus leucophthalmus; Furnariidae), a common participant of understory mixed-species flocks, exploited epiphytes more frequently when associated with mixed-species flocks. The utilization of epiphytes was opportunistic for most of the bird species recorded and occurred throughout the year with no seasonal variation.

Ventilation of the giant nests of Atta leaf-cutting ants: does underground circulating air enter the fungus chambers?

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

ATTENDANCE and CO-OCCURRENCE of BIRDS FOLLOWING ARMY ANTS IN THE ATLANTIC RAIN FOREST

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Toxic effects of leaves of Ricinus communis (Euphorbiaceae) to laboratory nests of Atta sexdens rubropilosa (Hymenoptera: Formicidae)

Laboratory nests of the leaf-cutting ant Atta sexdens rubropilosa Forel fed daily with leaves of Ricinus communis showed a gradual decrease in fungal garden volume, a higher ant mortality rate, and fungal garden extinction after 6 weeks. The mean oxygen consumption rate of these ants was higher than that of control ants collected from nests fed with leaves of Eucalyptus alba (Myrtaceae) suggesting one or more components of the leaves of R. communis had a direct physiological effect on the ants, in addition to inhibiting fungal garden growth.

Microbiological changes in the nests of leaf-cutting ants fed on sesame leaves

The number of bacteria and yeasts occurring in the organic matter inside the nests were determined both in colonies of leaf-cutting ants reared on Eucaliptus alba (control) or Sesamum indicum (experimental). Sesame leaves induce imbalance and nests usually die. In control nests the number of bacteria in newer sponge and in older sponge were similar (3.6 x 105 and 1.4 x 105 CFU/g, respectively) whereas in waste deposit the mean reached 7.3 x 107 CFU/g. The most Probable Number (MPN/g) of yeasts were 2.7 x 104, 1.3 x 105/g and 2.2 x 104 for newer sponge, older sponge and waste deposit, respectively. Using material from older sponge for comparison, the number of bacteria and yeasts reared on sesame leaves showed significant differences. The number of bacteria was 3.3 x 107 CFU/g, a value close to that found in waste deposit of normal (control) nests, whereas the number of yeasts was 6.7 x 105/g. These changes in microbial populations due to the effect of sesame leaf uptake could be a significant factor in nest imbalance and mortality when leaf-cutting ants are consuming toxic plants.

Duration of Protopolybia exigua exigua (de Saussure) nests and related aspects as influenced by phorid fly infestation (vespidae, polistinae, epiponini)

The main characteristics of 55 nests of Protopolybia exigua exigua were periodically evaluated in Ribeirão Preto, southeastern Brazil. Although the queens' life-span can eventually reach one year, nests barely thrive for six months because most of them are periodically invaded by the scavenger phorid fly, Megaselia aff. picta. Under heavy infestation the adult wasp population partially closes the nest entrance, migrates and constructs a new nest in the neighborhood. Afterwards the old-nest's entrance can be completely closed by the wasps which results in blocking the parasitoid flies inside. In the tropics, predation by ants is considered the main selective pressure which shaped most of the bionomic characteristics of Polistinae wasps. It is suggested that Megaselia can easily overcome the usual wasps defensive tactics just because they are so specialized against ants. Aerial raids, fast erratic-jerking movements, rapid and efficient oviposition behavior, etc. can eventually turn Megaselia into a very important enemy of some social wasps.

Multiple nymphoid reproductives in the nests of the neotropical termite, Armitermes euamignathus (Isoptera, Termitidae, Nasutitermitinae)

Armitermes euamignathus Silvestri (Termitidae, Nasutitermitinae) is a mound building termite that is common in Brazilian regions of the Cerrado vegetation. Multiple neotenic reproductives were found in three isolated nests of these species localized in other secondary habitats different from Cerrado vegetation. The number of second form queens was always higher than the number of secondary males. In two of these nests, the primary king was present along with the second form reproductives. Eggs and brood were found in the three nests but mature alates were present in only one. Multiple neotenic reproductives were never found in the studied Cerrado region where the nests contained only the primary pair. A study of oviposition rate between primary queens and nymphoid reproductives showed an increased number of eggs in the colony headed by neotenic reproductives.