Influence of Urban Landscape on Ants and Spiders Richness and Composition in Forests.

As large amounts of natural environments are lost due to urbanization, the role of remnant native vegetation in the preservation of biodiversity has become even more significant. Remnant native forest patches are essential refugia for flora and fauna and are crucial for the maintenance of ecosystem processes in urbanized landscapes. We evaluated the influence of landscape structure on ants and spiders associated with Atlantic Forest remnants in urban landscapes. We sampled 14 forest areas in the Metropolitan Region of Salvador and tested the effect of the landscapes' proportion of forest cover, mean landscape isolation, and mean landscape shape complexity on the taxonomic and functional richness and the community composition of both groups. The species collected were classified into functional groups based on behavioral attributes and environmental preferences. Overall, there were strong adverse effects of forest loss, decreased connectivity, and an increase in edge effects associated with the mean shape complexity of the forest remnants. However, the spiders responded to all three landscape structure characteristics whereas the ants only responded to the landscape mean shape complexity. Our findings indicate that the maintenance of urban forest habitats is essential for the conservation of biodiversity in the Metropolitan Region of Salvador and the preservation of ecological functions performed by species within the forest areas.

Influence of urban landscape on ants and spiders richness and composition in forests

As large amounts of natural environments are lost due to urbanization, the role of remnant native vegetation in the preservation of biodiversity has become even more significant. Remnant native forest patches are essential refugia for flora and fauna and are crucial for the maintenance of ecosystem processes in urbanized landscapes. We evaluated the influence of landscape structure on ants and spiders associated with Atlantic Forest remnants in urban landscapes. We sampled 14 forest areas in the Metropolitan Region of Salvador and tested the effect of the landscapes’ proportion of forest cover, mean landscape isolation, and mean landscape shape complexity on the taxonomic and functional richness and the community composition of both groups. The species collected were classified into functional groups based on behavioral attributes and environmental preferences. Overall, there were strong adverse effects of forest loss, decreased connectivity, and an increase in edge effects associated with the mean shape complexity of the forest remnants. However, the spiders responded to all three landscape structure characteristics whereas the ants only responded to the landscape mean shape complexity. Our findings indicate that the maintenance of urban forest habitats is essential for the conservation of biodiversity in the Metropolitan Region of Salvador and the preservation of ecological functions performed by species within the forest areas.

Ants of three adjacent habitats of a transition region between the cerrado and caatinga biomes: the effects of heterogeneity and variation in canopy cover.

Habitat heterogeneity and complexity associated with variations in climatic conditions are important factors determining the structure of ant communities in different terrestrial ecosystems. The objective of this study was to describe the horizontal and vertical distribution patterns of the ant community associated with three adjacent habitats in a transition area between the Cerrado and Caatinga biomes at the Pandeiros River, state of Minas Gerais, Brazil. We tested the following hypotheses: (1) the richness and composition of ant species and functional group structure changes between different habitats and strata; (2) habitats with higher tree species richness and density support higher ant species richness; and (3) habitats with lower variation in canopy cover support higher ant species richness. Sampling was conducted in three adjacent habitats and at three vertical strata. Ant species richness was significantly different among vertical strata. Ant species composition was different among both habitats and vertical strata and functional group structure was divergent among habitats. Partitioning of the diversity revealed that the diversity for the three components was statistically different from the one expected by the null model; α and ß 2 were higher and ß 1 was lower than the values expected by chance. Tree density and variation in canopy cover negatively affected ant species richness. The occurrence of different species and the changing of functional group structures in different habitats and strata suggest an ecological-evolutionary relationship between ants and their habitats and emphasize the need to implement local conservation strategies in the ecotones between biomes.

Mini-winkler extractor and pitfall trap as complementary methods to sample formicidae.

The aim of the present study was to evaluate the use of mini-Winkler extractor and pitfall traps as appropriate and complementary methods to sample ant communities in the phytophysiognomy mosaic in the Poconé Pantanal region, state of Mato Grosso, Brasil. Seven units were studied for landscape, located within a 25 km(2) collection area, formed by thirty 250-m transects, at 1-km intervals in a 5 × 5 km area. Five collection points were marked in each transect at 50-m intervals, totaling 150 points. A collection was made at each sampling point with mini-Winkler extractor and pitfall traps. Using the mini-Winkler extractor, 1,088 individuals were collected distributed in 20 genera and 55 species, with Solenopsis invicta Buren and Pheidole (gr. biconstricta) sp.1 as the most frequent ants. Using pitfall traps, 2,726 individuals distributed in 24 genera and 48 species were sampled and Dorymyrmex (gr. pyramicus) sp.1 and Pheidole (gr. biconstricta) sp.1 were the most frequent species. A significant difference between the methods was observed in measured species number. The Principal coordinates analysis discriminated two species groups exclusively sampled by the mini-Winkler extractor and another by the pitfall methods. Therefore, it was concluded that these methods were complementary for ant diversity inventories in the Poconé Pantanal region.

Filamentous fungi vectored by ants (Hymenoptera: Formicidae) in a public hospital in North-Eastern Brazil.

BACKGROUND: The increase in opportunistic fungal infections has led to the search for putative sources of contamination in hospital environments. AIM: Ants in a public hospital in Itabuna, north-eastern Brazil were examined for carriage of filamentous fungi. METHODS: During a year-long survey, ants from different hospital areas were sampled. Preference was given to locations where it was possible to observe ants actively foraging. The fungi found on the ants' integument were cultured and identified. FINDINGS: A total of 106 ant workers belonging to 12 species in 11 genera were collected. A total of 47 fungal strains was isolated from 40% of the ants (N = 42). We found 16 fungal species in 13 genera associated with the ant workers. The prevalent fungal genera were Aspergillus, Purpureocillium and Fusarium. The ants Tapinoma melanocephalum, Paratrechina longicornis and Pheidole megacephala were associated with six fungal genera; and four genera of fungi were associated with Solenopsis saevissima workers. Fungal diversity was higher in the following hospital areas: nursery, hospital beds, breastmilk bank and paediatrics. CONCLUSION: Ants act as carriers of soil and airborne fungal species, and ant control in hospital areas is necessary to prevent the dissemination of such micro-organisms.

Dinoponera lucida Emery (Formicidae: Ponerinae): the highest number of chromosomes known in Hymenoptera.

We report the remarkable karyotype of Dinoponera lucida, a Brazilian endemic ponerine ant. Its chromosome number is 2n=106, most of the chromosomes are acrocentric and of very small size, and the karyotype formula is 88A+18M. A chromosome pair of the AM(t) type is reported. This is the largest number of chromosomes reported for the Hymenoptera order until now.