SPATIAL-ORGANIZATION OF FORAGING ACTIVITY AND COLONIZATION BY COLONY EMIGRATION IN THE PHARAOH ANT, MONOMORIUM-PHARAONIS

Using food bait stations and colony trap nests, the spatial relation between the foraging activity of established colonies of the polygynous and unicolonial exotic pharaoh's ant, Monomorium pharaonis, and colonization by colony fragments was studied over an 8 month period in a large institutional setting in Brazil. Both foraging activity and colonizations demonstrated significant spatial clumping. However, colonizations were significantly negatively clumped spatially with respect to foraging activity. This suggests that the colonization strategy of this species under the studied conditions was that of complete habitat domination.

Biology and behaviour of the neotropical ant-mimicking spider Aphantochilus rogersi (Araneae: Aphantochilidae): nesting, maternal care and ontogeny of ant-hunting techniques

Aphantochilus rogersi is an ant-mimicking spider that preys exclusively on cephalotine ants. The spiders oviposit in close proximity to nests of the model ant Zacryptocerus pusillus, and emergent spiderlings tend to remain in the vicinity of natal egg sacs. Females of A. rogersi actively defend their egg sacs against approaching workers of Z. pusillus, but the latter may sometimes destroy the eggs. Feeding specialization on these ants is confirmed by more than 300 observations of young and adult A. rogersi carrying ant corpses in the held. Although A. rogersi possesses several behavioural traits which may reduce the risk of being injured by ants during subjugation, field and laboratory observations showed that social defence by Z. pusillus may cause mutilation to the spiders. Tests in captivity revealed an ontogenetic change in the prey-capture techniques employed by A. rogersi. Early-instar spiderlings can apparently only seize the ant's petiole tightly if they are able to approach the ant from the front. As the ant is paralysed, the spiderling positions itself vertically in relation to the substratum. Larger spiders, on the other hand, attack ants most frequently from behind, and seem better equipped to seize the ant's petiole firmly with their larger chelicerae. Owing to their greater strength, late-instar spiders are able to Lift the struggling ant aloft. The selection of a suitable oviposition site, the mother's ability to defend herself and the eggs from nearby ants, and the capacity to capture and subdue ants safely from emergence to maturity, are regarded as crucial traits inherent in the mimetic and feeding specialization by A. rogersi.

Female reproductive system of ant species of the subfamily ponerinae: Review and new data

Literature data about the female reproductive system of some species in the subfamily Ponerinae are presented. Our project objective to compile a report containing the largest possible number of data about the reproductive system in Ponerinae for a better understanding of the reproductive biology of these Insects, was completed.

A modified ant colony optimization algorithm modeled on tabu-search methods

An earlier model underlying the foraging strategy of a pachycodyla apicalis ant is modified. The proposed algorithm incorporates key features of the tabu-search method in the development of a relatively simple but robust global ant colony optimization algorithm. Numerical results are reported to validate and demonstrate the feasibility and effectiveness of the proposed algorithm in solving electromagnetic (EM) design problems.

REPRODUCTIVE STRATEGIES OF THE EXOTIC PHARAOH ANT, MONOMORIUM-PHARAONIS (L) (HYMENOPTERA, FORMICIDAE) IN BRAZIL

The production of sexual forms in laboratory colonies of Monomorium pharaonis was followed over a 19-month period. Cycles of production occurred at intervals of 4 months, with male investment inversely proportional to the number of gynes produced. There was a tendency for colonies to produce only males or females as total sexual production increased. Sperm counts of known-aged males suggest that they mate twice, in contrast to European populations. Sex-ratio was heavily female-biased, contrary to predictions for polygynous ant species.

ANT (HYM, FORMICIDAE) MOSAIC STABILITY IN BAHIAN COCOA PLANTATIONS - IMPLICATIONS FOR MANAGEMENT

Mapping and collection of ants in cocoa trees in a 1 ha plot in the south of Bahia, Brazil, revealed three dominant species of the ant mosaic: Wasmannia auropunctata, Ectatomma tuberculatum and Azteca chartifex spiriti. A. chartifex demonstrated a larger influence in the cocoa plantation due to its spatial and temporal (1 y) stability in the same cocoa trees, and its capacity for territorial expansion. The management of A. chartifex for controlling insect pests of cocoa is strongly recommended. Considerations of temporal permanence of mosaic dominant ants should be a necessary criteria for ant management in tropical tree crops.

Ant Group Effects on the Insecticide and Dye Flow Among Atta sexdens rubropilosa (Hymenoptera: Formicidae) Workers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Understorey fire propagation and tree mortality on adjacent areas to an Amazonian deforestation fire

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

Assessment of tropical forest degradation by selective logging and fire using Landsat imagery

Many studies have assessed the process of forest degradation in the Brazilian Amazon using remote sensing approaches to estimate the extent and impact by selective logging and forest fires on tropical rain forest. However, only a few have estimated the combined impacts of those anthropogenic activities. We conducted a detailed analysis of selective logging and forest fire impacts on natural forests in the southern Brazilian Amazon state of Mato Grosso, one of the key logging centers in the country. To achieve this goal a 13-year series of annual Landsat images (1992-2004) was used to test different remote sensing techniques for measuring the extent of selective logging and forest fires, and to estimate their impact and interaction with other land use types occurring in the study region. Forest canopy regeneration following these disturbances was also assessed. Field measurements and visual observations were conducted to validate remote sensing techniques. Our results indicated that the Modified Soil Adjusted Vegetation Index aerosol free (MSAVI(af)) is a reliable estimator of fractional coverage under both clear sky and under smoky conditions in this study region. During the period of analysis, selective logging was responsible for disturbing the largest proportion (31%) of natural forest in the study area, immediately followed by deforestation (29%). Altogether, forest disturbances by selective logging and forest fires affected approximately 40% of the study site area. Once disturbed by selective logging activities, forests became more susceptible to fire in the study site. However, our results showed that fires may also occur in undisturbed forests. This indicates that there are further factors that may increase forest fire susceptibility in the study area. Those factors need to be better understood. Although selective logging affected the largest amount of natural forest in the study period, 35% and 28% of the observed losses of forest canopy cover were due to forest fire and selective logging combined and to forest fire only, respectively. Moreover, forest areas degraded by selective logging and forest fire is an addition to outright deforestation estimates and has yet to be accounted for by land use and land cover change assessments in tropical regions. Assuming that this observed trend of land use and land cover conversion continues, we predict that there will be no undisturbed forests remaining by 2011 in this study site. Finally, we estimated that 70% of the total forest area disturbed by logging and fire had sufficiently recovered to become undetectable using satellite data in 2004. (C) 2010 Elsevier B.V. All rights reserved.

Trajectory of Water- and Fat-Soluble Dyes in the Grass-Cutting ant Atta capiguara (Hymenoptera, Formicidae): Evaluation of Infrabuccal Cavity, Post-Pharyngeal Glands and Gaster

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Occurrence of different gynandromorphs and ergatandromorphs in laboratory colonies of the urban ant, Monomorium floricola

Colonies of Monomorium floricola (Jerdon) in laboratory conditions showed gynandromorphic and ergatandromorphic specimens, the former with nine different combinations of male and female tissues and the latter with 6 different combinations. Their development from egg to adult was around 74.6 days for gynandromorphs, and 87.5 days for ergantandromorphs.