Spatial connectivity of aquatic macrophytes and flood cycle influence species richness of an ant community of a Brazilian floodplain

Despite the environmental and economic importance of Pantanal, there are few studies quantifying the influence of sazonality and spatial variation on biological diversity in this ecosystem. In this context, the present work aimed to study the assemblage of ants associated with macrophytes during the flood and dry period of Paraguay river, in marginal environments in the Pantanal of Porto Murtinho, Mato Grosso do Sul. We observed a wide variation in the temporal distribution of the diversity of the assemblages of ants, since from 37 species, 36 occurred in the dry and 20 in the flood period. Of the total of macrophyte species observed, in only 12.5% we found a more specific correlation with ants that were nesting in spaces provided by plants representing a total of 10.52% of the species analized.

First Cytogenetic Study Through Conventional Staining of The Ant Genus Blepharidatta Wheeler, 1915 (Hymenoptera: Formicidae: Attini)

Blepharidatta is a rare Neotropical ant genus in the Attini tribe of the subfamily Myrmicinae. It has only four valid species and among them Blepharidatta delabiei was recently described and there is little knowledge on its biology. This study is the first cytogenetic characterization for the genus Blepharidatta and also presents the biology of B. delabiei. Cytogenetic analyses revealed a karyotype 2n = 28 with acrocentric and metacentric chromosomes and a karyotypic formula (m: metacentric, a: acrocentric): 2K = 16m + 12a. We observed that ants of this species have diurnal habits with higher foraging activity in the afternoon and are possibly omnivorous as they accepted the baits used. The distance between colonies varied from 5 to 7 meters

Community Structure of Leaf-Litter Ants in a Neotropical Dry Forest: A Biogeographic Approach to Explain Betadiversity

This paper describes habitat and geographic correlates of ant diversity in Serra da Bodoquena, a poorly surveyed region of central-western Brazil. We discuss leaf-litter ant diversity on a regional scale, with emphasis on the contribution of each of the processes that form the evolutionary basis of contemporary beta diversity. The diversity of leaf-litter ants was assessed from a series of 262 Winkler samples conducted in two microbasins within a deciduous forest domain. A total of 170 litter-dwelling ant species in 45 genera and 11 subfamilies was identified. The data showed that the study areas exhibited different arrangements of ant fauna, with a high turnover in species composition between sites, indicating high beta diversity. Our analysis suggests that the biogeographic history of this tropical dry forest in the centre of South America could explain ant assemblage structure more than competitive dominance. The co-occurrence analysis showed that species co-occur less often than expected by chance in only two of the localities, suggesting that, for most of the species, co-occurrences are random. The assessment of the structure of the diversity of litter-dwelling ants is the first step in understanding the beta diversity patterns in this region of great biogeographic importance

Tree-Dwelling Ants: Contrasting Two Brazilian Cerrado Plant Species without Extrafloral Nectaries

Ants dominate vegetation stratum, exploiting resources like extrafloral nectaries (EFNs) and insect honeydew. These interactions are frequent in Brazilian cerrado and are well known, but few studies compare ant fauna and explored resources between plant species. We surveyed two cerrado plants without EFNs, Roupala montana (found on preserved environments of our study area) and Solanum lycocarpum (disturbed ones). Ants were collected and identified, and resources on each plant noted. Ant frequency and richness were higher on R. montana (67%; 35 spp) than S. lycocarpum (52%; 26), the occurrence of the common ant species varied between them, and similarity was low. Resources were explored mainly by Camponotus crassus and consisted of scale insects, aphids, and floral nectaries on R. montana and two treehopper species on S. lycocarpum. Ants have a high diversity on cerrado plants, exploring liquid and prey-based resources that vary in time and space and affect their presence on plants

Rediscovery and reclassification of the dipteran taxon Nothomicrodon Wheeler, an exclusive endoparasitoid of gyne ant larvae

The myrmecophile larva of the dipteran taxon Nothomicrodon Wheeler is rediscovered, almost a century after its original description and unique report. The systematic position of this dipteran has remained enigmatic due to the absence of reared imagos to confirm indentity. We also failed to rear imagos, but we scrutinized entire nests of the Brazilian arboreal dolichoderine ant Azteca chartifex which, combined with morphological and molecular studies, enabled us to establish beyond doubt that Nothomicrodon belongs to the Phoridae (Insecta: Diptera), not the Syrphidae where it was first placed, and that the species we studied is an endoparasitoid of the larvae of A. chartifex, exclusively attacking sexual female (gyne) larvae. Northomicrodon parasitism can exert high fitness costs to a host colony. Our discovery adds one more case to the growing number of phorid taxa known to parasitize ant larvae and suggests that many others remain to be discovered. Our findings and literature review confirm that the Phoridae is the only taxon known that parasitizes both adults and the immature stages of different castes of ants, thus threatening ants on all fronts.Peer reviewe

The Ant Genus Sphinctomyrmex

The ant genus Sphinctomyrmex has been represented in the Neotropical Region until now by a single species, S. stali, known only from sparse localities in southeastern Brazil. Two new neotropical species are herein described, S. marcoyi sp. n. and S. schoerederi sp. n. from workers collected in the Brazilian Amazon and Atlantic Forest, respectively. New records for Sphinctomyrmex stali are presented, and the species is redescribed together with discussions on its high morphological variation and the identity of its type specimen. A key for the neotropical Sphinctomyrmex workers, images of all species presently known, and a distribution map are supplied

Avaliação de duas técnicas de translocação de serrapilheira sobre as assembleias de aranhas (Arachnida: Araneae) e formigas (Hymenoptera: Formicidae)

Due to the current rhythm of ecosystem destruction, the development of new techniques aiming at the conservation of forest remnants and their biota is urgent. Our objective was to compare two techniques of leaf-litter translocation (with and without  withdrawing the pre-extent litter layer), through observations on spider and ant richness and assemblage composition, in order to define the best way to perform translocation. The study was carried out in two Brazilian Atlantic rain forest remnants  (called releaser and receptor fragments) in Salvador, State of Bahia, Brazil. A comparison between the faunas of both fragments was performed before translocation and a significant difference was found both in their richness and composition, which is an essential condition to carry out the experiment. A small scale environmental characterization] was made in order to choose similar units capable of  minimizing the stress on leaf-litter organisms living there. Both for spiders and ants, the species richness increased in units that received leaf-litter and it was higherfor spiders in units where the pre-extent litter had not been removed. For the ants, the two forms of translocation seem to be efficient. Nevertheless, taking into account the two groups of organisms, it is suggested that the translocation must be done maintaining the pre-extent leaf-litter.Key words: conservation, litter, fauna manipulation, spiders, ants.Com o ritmo atual de destruição dos ecossistemas surge a necessidade de se investir em técnicas que visem à conservação dos remanescentes florestais e das suas espécies. Nosso objetivo foi comparar duas técnicas para translocação da serrapilheira (com e sem a retirada da camada de serrapilheira preexistente), observando como varia a riqueza e composição de aranhas e formigas no local da translocação, a fim de definir a melhor forma de realizá-la. O estudo foi realizado em dois remanescentes de Mata Atlântica (fragmento doador e receptor) localizados em Salvador (BA). Antes da translocação foi realizada uma comparação de ambas as faunas, entre os fragmentos, e foi  encontrada diferença significativa tanto na riqueza quanto na composição. Assim pôde-se realizar o experimento. Para tanto, foi realizada a  caracterização ambiental a fim de translocar a serrapilheira para as unidades mais similares na  tentativa de minimizar o estresse dos organismos. A riqueza em espécies tanto de aranhas quanto de  formigas aumentou nas unidades que receberam a serrapilheira, sendo para aranhas mais elevada nas unidades onde não foi retirada a serrapilheira preexistente. Já para as formigas as duas formas parecem eficientes. Contudo, levando em consideração os dois grupos, propõe-se que a translocação deve ser feita mantendo a serrapilheira preexistente.Palavras-chave: conservação, serrapilheira, manipulação da fauna, aranhas, formigas

A temporary social parasite of tropical plant-ants improves the fitness of a myrmecophyte

Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant-plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant-myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca-Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees' fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree

Assembléias de Formicidae epigéas no entorno do Parque Nacional da Chapada Diamantina, Bahia, Brasil

Ants at four localities were studied in the surroundins of the National Park of Chapada Diamantina, central region of the State of Bahia, Brazil. Vegetation belongs to the Atlantic forest biome (Sazonal Semideciduous Forest), but it is regionally surrounded by other vegetation formations, mainly of the caatinga and altitude field biomes. In each one of the four areas, 50 samples of ants were collected with a Winkler extractor and anoother 50 with pitfall traps. A total of 191 species distributed in 47 genera was found. The Winkler trap was most efficient in species capture. The communities of the two areas closer to the National Park, at Lençois presented greater similarity between themselves and larger species number, perhaps because they had been less used by humans in the last 40 years, than the two other areas studied, situated in farms and more distant to the Park. The comparative analysis of the similarity indices, calculated from the capture results obtained with the pit-fall traps and Winkler extractor, indicates that the two trees made from the results of all four areas are identical. Although this result was unexpected, it shows that whatever the collection method and the fauna segment studied, the relative similarity between series is respected. If this observation is verified under additional experimental conditions and biomes, it indicates that if the purpose is to use ants as bioindicators, several sampling techniques can be indiscriminately used for the comparative evaluation of ant assemblages, even if different strata are sampled for their fauna, with no impact on the conclusions that can be drawn about their characteristics of degradation or conservation.Foram realizadas coletas de Formicidae em quatro localidades situadas no entorno do Parque Nacional da Chapada Diamantina, região central do Estado da Bahia. A vegetação pertence ao bioma Mata Atlântica (Floresta Estacional Semidecidual), mas é regionalmente circundada por outras formações vegetais, sobretudo dos biomas caatinga e campo rupestre. Em cada uma das quatro áreas, foram coletadas 50 amostras de formigas da serapilheira com o extrator de Winkler e outros 50, com armadilhas de tipo pitfall. Foi encontrado um total de 191 espécies, distribuídas em 47 gêneros. A armadilha de Winkler foi a mais eficiente na captura de espécies. As comunidades das duas áreas situadas mais próximas ao Parque Nacional, em Lençóis, foram as que apresentaram maior similaridade entre si e maior número de espécies, talvez porque foram menos utilizadas pelo homem nos últimos 40 anos do que as duas outras áreas estudadas, situadas em fazendas mais distantes do Parque. A análise comparativa dos índices de similaridade, calculados a partir dos resultados das capturas realizadas com as armadilhas pit-fall e extrator de Winkler, indica que os dois agrupamentos relativos às quatro áreas estudadas são estritamente iguais. Apesar de esse resultado ser surpreendente, ele mostra que, qualquer que seja o método de coleta, isto é, o segmento de fauna amostrada, a similitude relativa entre series amostrais é respeitada. Se essa colocação se verificar em outras condições experimentais e outros biomas, ela indica que, em caso de uso das formigas como indicadores biológicos, diversas metodologias de amostragens poderiam ser indiscriminadamente utilizadas na avaliação comparativa de assembléias de Formicidae, mesmo se forem estudados estratos da fauna diferentes, sem prejuízo das conclusões que podem ser retiradas sobre as características de degradação ou de conservação de cada uma

As formigas poneromorfas do Brasil

Resultado do projeto "Rede Multidisciplinar de Estudos sobre Formigas Poneromorfas do Brasil", o livro apresenta um conjunto de estudos originais ou revisões bibliográficas que focalizam o comportamento, desenvolvimento e contribuições das formigas poneromorfas para o ecossistema