The little fire ant, Wasmannia auropunctata, has been increasing in importance as an exotic pest. Here we review published and unpublished information on its distribution, ecology, impact, and control. Wasmannia auropunctata occurs throughout most of the warmer parts of the New World, from subtropical Argentina to subtropical Mexico and through much of the Caribbean, though it is not clear whether this species is native to this entire region. During the past century, exotic populations of W. auropunctata have become established in numerous other places, including the Galapagos Islands, West Africa (Gabon, Cameroon, and possibly the Republic of Congo and the Democratic Republic of Congo), Melanesia (New Caledonia, Solomon Islands, Vanuatu, and possibly Tuvalu), Polynesia (Wallis and Futuna and Hawaii), the mainland US (Florida and possibly California), and on subtropical Atlantic islands (the Bahamas and Bermuda). The latitudinal range of known outdoors populations of W. auropunctata is from 32o40'S in Argentina to 32o20'N in Bermuda. Wasmannia auropunctata is also a greenhouse pest in more temperate regions, such as England and Canada. In many areas, W. auropunctata can be a significant agricultural pest, not only stinging agricultural workers, but also enhancing populations of Homoptera. Homoptera cause damage both through sapping plants of nutrients and by increasing the occurrence of diseases, including viral and fungal infections. In addition, W. auropunctata has negative impacts on many animals, both invertebrates and vertebrates, though most reports on such impact have been anecdotal. The impacts of W. auropunctata populations seem to be most severe on tropical islands where it is not native, such as the Galapagos, New Caledonia, and the Solomon Islands. Reports of widespread blindness in both domestic and native mammals caused by W. auropunctata stings deserve serious attention. Chemical control of W. auropunctata may be possible for small exotic populations spread over a few dozen hectares or less. For large exotic infestations, the only hope for long-term control appears to be classical biocontrol.

The little fire ant, Wasmannia auropunctata: distribution, impact, and control.

We studied the structure and composition of communities of social wasps associated with the three insular ecosystems: mangrove swamp, the Atlantic Rain Forest and the 'restinga'- lowland sandy ecosystems located between the mountain range and the sea. Three hundred and ninety-one nests of 21 social wasp species were collected. The diversity of wasps found in each ecosystem was significantly correlated to the diversity of vegetation in each of the three physiognomies, (r2 = 0.85; F(1.16) = 93.85; P < 0. 01). The Tropical Atlantic Forest physiognomy had higher species richness (18 species), followed by the restinga (16 species) and the mangrove (8 species) ecosystems.

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Diversity and community structure of social wasps (Hymenoptera: Vespidae) in three ecosystems in Itaparica island, Bahia State, Brazil.

This survey of the ant fauna in a native forest and in three plantations of Eucalyptus of 6, 20 and 106 months of age was conducted in August 1992. Sampling consisted of two 100 m transects per area along which 10 pitfall traps were placed for 7 days, after which they were replaced for traps baits with sardines, crackers and sugar laid during one hour per day. In addition hand collecting was performed on soil, litter, trees and shrubs for five non consecutive hours in each area. A total of 121 species belonging to 5 subfamilies and 50 genera was collected. The calculated Hill indices have indicated that in the native area there was a lower dominance and a higher species diversity. In the eucalipt there was a tendency towards reduced dominance and increased diversity as the stands grew older.

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A fauna de formigas em povoamentos de eucalipto e mata nativa no estado do amapá

Fire represents an important disturbance to ant communities in areas of fire regime. Otherwise, little is known about the effects of fire on ant communities in areas of non-fire regimes, such as in the Amazonian region. We evaluated the long-term effect of fire on ant species richness in a rain forest (Bacaba Plateau) burned 15-years ago and compare our data with the data of primary unburned forest. A total of 85 ant species distributed in 21 genera and 14 tribes were collected; among them, 72 and 44 species were found on the litter and vegetation, respectively. The fire damaged forest studied supports an intermediate richness of ants when compared to a primary unburned rain forest in the same region. A comparative analysis of ant species richness showed that the Bacaba Plateau presented a different ant fauna when compared with the primary unburned forests, suggesting that fire can alter ant species composition. Although, our results cannot be conclusive on the effects of fire on ant community, they represent a pioneer data on human induced fire in tropical rain forests.

A 15-year post evaluation of the fire effects on ant community in an area of Amazonian forest

This investigation was conducted to compare the soil ant fauna of an eucalypt plantation to that of a second growth forest; both areas located in the Zona da Mata of Minas Gerais, Brazil. Tuna fish, honey and cracker baits were used to collect ants along a transect and pitfall traps were distributed in central 900 m of each site. A total of 64 species belonging to 26 genera were collected in the 12 weekly samples; 54 species were captured in the forest and 45 in the Eucalypius granais plantation. A total of eight species presented frequencies above 10% in at least one area. Species richness was higher in the second growth forest. Additional studies should be considcred for further generalizations of the results.

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M.C Loureiro

Papers

Ordenacao de comunidades de formicidae em quatro agroecossistemas em vicosa, minas gerais