Search

The development of easily observable measures of restoration success is essential for monitoring of the ambitious proposed global restoration targets (e.g. The Bonn Challenge; New York Declaration on Forests). Systematic reviews with meta-analyses are a good way to evaluate the performance of different organisms in the monitoring of ecological restoration. Among the arthropods, ants have a long history in environmental monitoring. We compiled a data set and performed a global meta-analysis encompassing studies conducted in different ecosystems around the world to investigate whether richness and composition of species or functional groups (FG) of ant communities can be predicted during the restoration process. Moreover, we aimed to understand the influence of restoration technique (natural regeneration or active restoration), ecosystem type (temperate or tropical), and past land use (mining or pasture) on ant communities in areas undergoing restoration processes. Notwithstanding the varied conditions in which the studies were carried out, our meta-analysis showed that reestablishment of ant FG takes place more quickly than species richness. The recovery of ant diversity is faster in tropical ecosystems and areas under natural regeneration can have higher ant diversity than the reference areas. In temperate ecosystems, mined areas under restoration are less likely to recover the number of species than FG richness. Both species and FG composition were less predictable in our meta-analysis. As the publication of new datasets is increasing, we hope that future meta-analyses can build on the present study to further describe and understand the patterns in ant communities to be used as indicators of ecosystem restoration.

Urban green recreational spaces may provide habitat for animals and plants. We investigated the importance of urban public parks in the city of Rio de Janeiro with regard to the conservation of ant species by comparing both the structure of the ground-dwelling ant community between urban parks and continuous forests and the influence of environmental factors on possible differences. Fifteen urban areas were sampled (5 isolated parks, 5 non-isolated parks and 5 forest areas). Ants were sampled at sardine bait stations and through manual/visual searching in quadrats around the baits. We identified 120 ant species (4 exotic species) distributed across 38 genera and 7 subfamilies. The four exotic species were Monomorium floricola, Paratrechina longicornis, Pheidole megacephala and Tetramorium simillimum. Both the taxonomic and functional diversity of ground-dwelling ants were higher in continuous forests, followed by non-isolated and then isolated urban parks. Environmental factors were found to be key drivers influencing the differences in ant community structure among continuous forests and urban parks. Soil compaction and canopy cover predicted the diversity patterns of the taxonomic and functional compositions of the ant communities. The ant species in the study areas exhibited a non-random pattern of distribution and a spatial association of species segregation. There was high spatial turnover of ant species in the study areas, indicating that conservation efforts are required in all studied urban areas, not just those areas considered to be species rich. Therefore, we need to conserve more species in more areas, not necessarily those high in richness.

Ants, an ecologically successful and numerically dominant group of animals, play key ecological roles as soil engineers, predators, nutrient recyclers, and regulators of plant growth and reproduction in most terrestrial ecosystems. Further, ants are widely used as bioindicators of the ecological impact of land use. We gathered information of ant species in the Atlantic Forest of South America. The ATLANTIC ANTS data set-which is part of the ATLANTIC SERIES data papers-is a compilation of ant records from collections (18,713 records), unpublished data (29,651 records), and published sources (106,910 records; 1059 references), including papers, theses, dissertations, and book chapters published from 1886 to 2020. In total, the data set contains 153,818 ant records from 7,636 study locations in the Atlantic Forest, representing 10 subfamilies, 99 genera, 1,114 ant species identified with updated taxonomic certainty, and 2,235 morphospecies codes. Our data set reflects the heterogeneity in ant records, which include ants sampled at the beginning of the taxonomic history of myrmecology (the nineteenth and twentieth centuries) and more recent ant surveys designed to address specific questions in ecology and biology. The data set can be used by researchers to develop strategies to deal with different macroecological and regional-wide questions, focusing on assemblages, species occurrences and distribution patterns. Furthermore, the data can be used to assess the consequences of changes in land use in the Atlantic Forest on different ecological processes. No copyright restrictions apply to the use of this data set, but we request that authors cite this data paper when using these data in publications or teaching events.

A challenge for studies on the organization of ant assemblages in forest ecosystems is to disentangle the causal effects of species occurrences. The structural and functional attributes of trees can act as environmental filters for ground-dwelling ant species influencing resource availability and the microclimate. The biotic interactions, especially competition, can work together with plant characteristics influencing ant species occurrences. To test the importance of tree traits and species interactions on co-occurrence patterns of ants, we collected ground-dwelling ants, with pitfalls and litter sampling, beneath the canopies of four tree species during the rainy and dry seasons in a restored forest. We used five predictors (tree identity, crown size, trunk circumference, litter depth, and leaves density) to model the presence probabilities of ants . Hence, we applied habitat constrained null models in pairwise analyses to disentangle the causal effects of ants co-occurrences. The random pattern predominated in the assemblages, making up 96% of all possible species pairs combinations. Overall, 50% of the species pairs that showed nonrandomness in the ant occurrences were interpreted as resulting from environmental filters, 36% as negative associations and 14% as positive associations. Additionally, we found that the effects of season and the sampling technique on the ant assemblages were also important. We suggest that the ideas of the trees as templates and the paradigm of competition are both useful for understanding pairwise occurrence patterns in ant assemblages, and can be tested using tree traits as predictors in ant species distribution models for running constrained null models.

Sphex ingens is one of 30 species in the family Sphecidae that occur in the state of Rio de Janeiro. However, details of the behavior and sexual selection of natural populations of this wasp species have only recently been unveiled. In addition, the knowledge of its ecology is still poor. This is the first study on the feeding behavior interactions between S. ingens and prey captured to feed its larvae. Paralyzed prey were collected manually at the sites of wasp nests on Aventureiro Beach, Ilha Grande, Brazil during the provisioning activity of marked female S. ingens. All prey were preserved, their sex and sexual maturity were determined, and they were identified to the lowest possible taxonomic level. The body mass and size of the prey and female wasps were measured. Sphex ingens females captured only Pleminia vicina and Meroncidius sp. The body masses of wasps and katydids were positively correlated. The body mass of captured katydids was significantly dependent on the wasp’s wing length. Most of the prey were adult females, but the differences did not confirm possible preferences, as those values can be related to differences in the distribution and fluctuation in the population density of prey species and to the individual foraging strategies of female wasps. However, the predisposition to predatory specialization exhibited by S. ingens populations in Ilha Grande and elsewhere suggests that this interaction can be an important source of mortality for populations of pseudophylline katydid species.

This study aimed to evaluate the ant fauna in three different land-use systems: pasture, eucalyptus plantation and secondary forest, in southeastern Brazil. The ant fauna was collected with standardized pitfall traps. Forty-seven ant species were collected, belonging to 24 genera and six subfamilies. The total ant species richness was significantly higher in secondary forest (29 species) and eucalyptus plantation (25 species) when compared to the pasture (17 species), with no significant difference between the secondary forest and eucalyptus plantation. The species composition differed significantly between the three land-use systems. The frequency distributions of ant guilds in eucalyptus plantation and secondary forest differed significantly from the frequency in the pasture. The results demonstrated the importance of natural forests for the conservation of biological diversity of the Atlantic Forest, but they also indicated that eucalyptus plantations, with native understory plants, can harbor considerable ant diversity.

RESUMO: As formigas-cortadeiras são consideradas os herbívoros dominantes da Região Neotropical e, portanto, estudos a respeito dos seus múltiplos efeitos sobre outros organismos e processos ecossistêmicos são relevantes. O presente estudo tem como objetivo determinar se ninhos de Atta sexdens (Linnaeus, 1758) podem afetar a estrutura da assembleia de artrópodes do solo em um fragmento de Mata Atlântica. Além disso, a fim de determinar os prováveis mecanismos que explicam a possível modificação na estrutura da fauna de artrópodes, foram testadas duas hipóteses: I) Hipótese da Serrapilheira: A. sexdens reduz a disponibilidade de serrapilheira nas proximidades do ninho; II) Hipótese dos Fatores Abióticos: A. sexdens modifica as condições microclimáticas ao redor do seu sítio de nidificação causando aumento da temperatura e luminosidade e redução da umidade relativa do ar. O estudo foi conduzido na Reserva Ecológica de Guapiaçu, junto à cidade do Rio de Janeiro, Brasil. Coletamos amostras de serrapilheira a intervalos de oito metros da borda dos ninhos de A. sexdens, ao longo de um transecto linear de 32 metros, para extração da assembleia de artrópodes e para estudar a estrutura da serrapilheira. Também medimos as temperaturas do ar e do solo, a luminosidade e a umidade relativa do ar onde coletamos as amostras de serrapilheira. Não detectamos qualquer efeito da presença do ninho sobre a riqueza, abundância e composição de artrópodes do solo no fragmento florestal estudado. Esse resultado foi provavelmente influenciado pelo fato de que os ninhos de A. sexdens estudados não afetam a disponibilidade de serrapilheira e as condições microclimáticas ao seu redor. Assim, concluímos que os múltiplos efeitos que as formigas-cortadeiras podem ter em uma floresta devem ser dependentes da espécie. ABSTRACT: Leaf-cutting ants are considered dominant herbivores in the Neotropical region and, therefore, the studies about their multiple effects on other organisms and ecosystem process are relevant. The present study aims to determine if Atta sexdens (Linnaeus, 1758) nests can affect the soil arthropods assemblage structure in an Atlantic forest fragment. Also, so as to determine the probable mechanisms that explain a possible modification in the arthropods fauna structure were tested two hypothesis: I) Litter Hyphotesis: A. sexdens reduce the litter availability in the nest proximities; II) Abiotic Factors Hyphotesis: A. sexdens modifies the microclimatic conditions around of its nidification site, producing a increasing of temperature and luminosity and reduction in relative air humidity. The study was conducted at the Reserva Ecológica de Guapiaçu, near Rio de Janeiro city, Brazil. We collected litter samples, at intervals of eight meters from edge of A. sexdens nests, along a linear transect of 32 meters, for the extraction of arthropods assemblage and to study the litter structure. We also measured the air and soil temperature, the luminosity and the air relative humidity where we collected the litter samples. We didn’t detect any effect of nest presence on richness, abundance and composition of soil arthropods in the forest fragment studied. Probably, these result was influenced because of A. sexdens nests studied don’t affect the litter availability and the microclimatic conditions around them. Thus, we conclude that the multiple effects that leaf-cutting ants can have on forest may be species dependent.

RESUMO A contínua substituição da cobertura florestal pelo cultivo agrícola e a urbanização causaram alterações na maior parte do bioma Mata Atlântica no Brasil. O entendimento da interação entre os fatores físicos, antrópicos e da cobertura vegetal em uma paisagem é de fundamental importância para oferecer subsídios ao planejamento territorial de forma sustentável. Este estudo investigou a influência da altitude, declividade e orientação das vertentes na cobertura florestal em três diferentes paisagens no município de Vassouras, RJ. No geral, as áreas analisadas apresentaram a cobertura florestal fragmentada, porém foi observada uma paisagem com maior cobertura florestal do que pastagens. Entre as variáveis analisadas, a altitude e a declividade apresentaram uma relação positiva com a cobertura florestal. As paisagens estavam inseridas em diferentes contextos socioeconômicos que podem também determinar a distribuição da cobertura florestal atual. A região estudada oferece atributos socioambientais específicos de cada paisagem, cuja compreensão deve ser útil ao planejamento ambiental. ABSTRACT The continuous replacement of forest covers for crops and urban areas changed most of the Atlantic Forest biome in Brazil. Hence, understanding the interaction between the forest cover, physical and anthropic factors in a landscape is essential in order to provide subsidies for sustainable land use. The present study aimed at investigating the influence of the altitude, declivity, and slope orientation on the forest cover of three landscapes in the municipality of Vassouras. In general, Vassouras showed fragmented forest covers, but we observed a landscape covered more by forests than pastures. Among the variables analyzed, altitude and declivity showed a positive relationship with forest cover. The analyzed landscapes were inserted in different socio-economical contexts, which can also affect the current forest cover distribution. The socio-environmental attributes of those landscapes are specific and their understanding can be strategic for environmental planning.

Fragmentation of the habitat is a major threat to biodiversity in Atlantic forest. Parasitoids seem to be particularly susceptible to habitat fragmentation. This study evaluated whether habitat fragmentation affected the interactions between phorid parasitoids and their Acromyrmex leaf-cutting ant host. Host density, and parasitoid species richness, abundance and proportion of nests with phorids were compared for a fragmented landscape and a well-preserved continuous forest in the Atlantic forest in Rio de Janeiro. Five Acromyrmex species and seven species of phorid parasitoids were found, most of them attacking exclusively Acromyrmex niger (Smith). Host nest density was similar in continuous and fragmented forests, and host species density was higher in fragmented forest. Parasitoid species richness, abundance and proportion of ant nests with phorids were higher in the continuous forest. This work showed for the first time the negative effect that forest fragmentation has on parasitoid species of Acromyrmex ants, apparently due to phorid inability to reach fragments. However, even when phorid abundance was considerably reduced in forest fragments, phorids of some species were able to parasitize ants there. In addition, the quantitative interactions among Acromyrmex ants and their parasitoids in Atlantic forest are described for the first time.

Changes in species composition and an increase in the probability of local or regio nal extinctions alone are considered alarming consequences of human disturbances. However, these changes bring other damages that have passed unnoticed by scientists, such as the loss of ecological interactions. In the present study, we assessed fragments of secondary forest and pastures focusing on two aspects of the seed dispersal process: removal rate and dispersal distance. We collected data in forest fragments named Forest 1 (6 ha), Forest 2 (36 ha), and Forest 3 (780 ha), and in a pasture in the municipality of Vassouras, Rio de Janeiro, southeastern Brazil. In each site, we established 40 observation stations containing six seeds of Carica papaya L. (papaya) and monitored seed removal for 2 h at each station. Seventeen ant species removed a total of 316 seeds (32.92% of the seeds). The species that removed the highest number of seeds was Pachycondyla striata Fr. Smith, followed by Odontomachus chelifer (Latreille). The seed removal rate was significantly higher (P < 0.05, Tukey test) in the forest fragment where larger species were more frequent. The average removal distance was significantly longer in two out of three forest fragments (P < 0.05, Tukey test). Larger ants removed more seeds and for longer distances. Hence, seed dispersal was increased by the presence of large-bodied ant species and their high frequency in forest fragments seed dispersal. Sociobiology An international journal on social insects

Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and natural areas. Hosts of parasitoids in urban areas may suffer from a double threat of habitat destruction by urbanization and parasitism pressure. Moreover, the parasitoids themselves might be at risk if they are specialists. Here, we studied whether Atta robusta (Hymenoptera, Formicidae), which is on the red list of Brazilian threatened species, suffers from higher parasitism pressure in an urban area compared to a natural one. In addition, we determined whether their specialist parasitoids, Eibesfeldtphora breviloba and Myrmosicarius exrobusta (Diptera, Phoridae), are in risk and evaluated whether they are influenced by habitat structure, temperature, humidity, ant traffic, and time of the day. The study was carried out in an urban park and in a natural protected area in the city of Rio de Janeiro. In each site we chose an open area and a closed area (forest) and sampled nine nests in each area. We found that parasitism pressure was similar in urban and natural areas, with the same two parasitoid species present in both areas. The main difference was related to habitat structure, since M. exrobusta was mainly present in open areas while E. breviloba was almost exclusively found in closed areas. Myrmosicarius exrobusta was not present during the hottest midday times, and its abundance was negatively correlated to vapor pressure deficit. These results suggest that green areas can be an important component in efforts to conserve diversity in urban areas. However, the complexity of the habitats in those areas is a fundamental issue in designing urban parks.

Made available in DSpace on 2018-11-26T15:37:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-09-01 Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) The present study aimed at assessing the effects of climate seasonality on poneromorph ants in the Brazilian Amazon, by studying variations in composition, richness, and taxonomic and functional diversity. The study was carried out in the Tapirape-Aquiri National Forest, southeastern Para State. We collected poneromorph ants in three areas of native forest with pitfall traps and sardine baits on the ground and vegetation, in two dry and rainy seasons. We collected 46 species of poneromorph ants, which belong to two subfamilies and eleven genera. The species composition, richness and taxonomic diversity did not vary significantly between seasons. There was no significant difference in the frequency of species of functional groups between dry and rainy seasons. There was no significant difference in the average richness and average diversity of functional groups between the dry and rainy seasons. In our study we found no seasonal differences in composition, taxonomic and functional richness and diversity of poneromorph ants in the Amazon, which is useful for future studies that aim at using those ants as bioindicators. In addition, the identification of the species made in the present study has special relevance as it contributes to advance the knowledge of poneromorph ant diversity in the Amazon. Univ Fed Rural Rio de Janeiro, Seropedica, RJ, Brazil Univ Fed Rural Rio de Janeiro, Tres Rios, RJ, Brazil Ctr Univ Volta Redonda UniFOA, Volta Redonda, RJ, Brazil Univ Estadual Paulista, Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Sao Jose Do Rio Preto, SP, Brazil FAPERJ: 101.472/2010

Em todo o mundo, a sociedade e o poder publico vem se mobilizando para criar mecanismos que garantam a conservacao da diversidade biologica. Em relacao aos ecossistemas florestais, o desmatamento e a consequente reducao e fragmentacao do habitat sao apontados como fortes ameacas a biodiversidade. Assim, este trabalho objetivou apresentar e discutir estrategias que podem ser utilizadas para a conservacao da diversidade biologica em paisagens florestais fragmentadas. No Brasil, os esforcos conservacionistas tem se concentrado na manutencao de grandes extensoes de florestas em Unidades de Conservacao da Natureza e outras areas protegidas. A recuperacao de areas degradadas, atraves de reflorestamentos com especies nativas e a implantacao de corredores ecologicos, tambem sao acoes importantes para a melhoria das condicoes ecologicas e para a conservacao da diversidade biologica. Como, na realidade atual, as areas com florestas estao inseridas em uma matriz de pastagens e areas agricolas, diversos autores sugerem ainda que os agricultores devam ser incluidos nos planos de conservacao da biodiversidade, principalmente atraves do estimulo a adocao de meios produtivos diversificados e praticas conservacionistas. Alem disso, a educacao ambiental deve ser utilizada para que a populacao adquira consciencia ambiental e, assim, valorize e atue na defesa dos fragmentos florestais. Todavia, apesar das estrategias utilizadas para a conservacao das especies terem se mostrado uteis, quando aplicadas isoladamente, elas apresentam falhas. Dessa maneira, e necessario adotar metodologias que envolvam varias dessas estrategias de maneira integrada. Abstract All over the world, society and public authorities have been joining efforts to create mechanisms that ensure biodiversity conservation. In forest ecosystems, deforestation and the consequent habitat reduction and fragmentation have been pointed out as strong threats to biodiversity. Therefore, this study aimed at presenting and discussing strategies that can be used for biodiversity conservation in fragmented forest landscapes. Conservation efforts have been focused on the maintenance of large extensions of forests in reserves and other protected areas. The restoration of degraded areas through reforestation with native species and the implementation of ecological corridors are also important actions for the improvement of ecological conditions and for biodiversity conservation. Since currently forest areas are inserted in a matrix of pastures and agricultural areas, several authors suggest that farmers should be included in biodiversity conservation plans, mainly through incentives for diversified production systems and conservation practices. Moreover, environmental education must be used to raise public environmental consciousness and, hence, make people appreciate and help to preserve forest fragments. However, although the strategies used for species conservation have been proved useful, they do not work well when applied separately. Therefore, it is necessary to use approaches that integrate several strategies.

A regra de equivalência energética (REE) propõe que o uso de energia independe do tamanho corporal da espécie. O tamanho e a abundância de formigas da serapilheira, coletadas em floresta ombrófila usando armadilhas pitfall e extrator de Winkler, foram usados no teste da REE. Os dados de abundância obtidos da extração de Winkler confirmaram a REE, enquanto os dados provenientes das armadilhas pitfall rejeitaram. A combinação das abundâncias estimadas pelas duas técnicas tanto aceitou quanto rejeitou a REE. Estudos posteriores deveriam focar a interação entre a técnica de coleta e o tipo de habitat no teste da REE para comunidades de formigas. The Energetic Equivalence Rule (EER) states that species tend to consume energy independent of their body size. Here, the EER was tested for litter ants using body size and abundance data. Rainforest ants were obtained using pitfall traps and Winkler extractor. The abundance data from the Winkler extractions confirmed the EER, while the pitfall traps rejected it. Combination of abundance from pitfall catches and Winkler extractions either confirmed or rejected the EER. Further studies should focus on the interaction between sampling techniques and habitat types in the test of EER for ant communities.

As formigas são componentes funcionais importantes em florestas tropicais devido aos papéis ecológicos que exercem, à grande biomassa e à riqueza de espécies. Embora a Mata Atlântica seja um dos ecossistemas mais bem estudados no Brasil, ainda faltam informações sobre a diversidade de formigas nos fragmentos florestais do Estado do Rio de Janeiro. A riqueza e composição da assembléia de formigas em floresta ombrófila de encosta na ilha da Marambaia (RJ) foi estudada através de um inventário estruturado em uma área de 0,6 ha. Armadilhas do tipo "pitfall" e coletas manuais foram empregadas na serapilheira e sobre a vegetação entre os meses de janeiro e julho de 2004. Um total de 29 gêneros e 82 espécies foi encontrado na amostragem. A abundância e a riqueza de espécies foram maiores nas amostras de março do que de julho. Já a eqüitatividade e diversidade de formigas nas amostras não foram influenciadas pela época da coleta. As amostras de formigas em galhos mortos adicionaram seis espécies à lista, acrescentando informações sobre a biologia das espécies. As amostras sobre plantas totalizaram 32 espécies de formigas, das quais 12 foram exclusivas, como as espécies de Pseudomyrmex e algumas de Crematogaster e Pachycondyla. Este estudo pretende contribuir para o desenvolvimento de prioridades conservacionistas em um dos ecossistemas mais ameaçados do mundo. Ants are an important functional component in tropical forest due to their ecological roles, biomass and species diversity. Although the Atlantic Forest is one of the best studied ecosystems in Brazil, there is a lack of information about ant diversity in forest fragments of the state of Rio de Janeiro. The composition and richness of the ant fauna from atlantic slope rain-forest in Marambaia island-RJ were assessed by the structured inventory in an area of 0.6 ha. Pitfalls traps and hand collecting were used for sampling ants in the litter and on vegetation from January to July/2004. A total of 29 genera and 82 species were found in this survey. Ant abundance and richness were higher in March than in July samples. Eveness and diversity of ants in the samples were not affected by the time of the year. Collections of ants from dead twigs yielded an additional seven species and provided information about the ant biology. Sampling ants on plants resulted in 32 species but 12 species were not recorded in litter samples. Some species were recorded exclusively on vegetation, such as Pseudomyrmex, Crematogaster and Pachychondyla species. This study aims to contribute to the development of conservation priorities in one of the most threatened ecosystems in the world.

The objective of the present study was to test whether environmental complexity influences the morphology of leaf litter worker ants, as predicted by the size-grain hypothesis. We collected data from three types of vegetation (shrubby, shrubby-arboreal, and arboreal) in Restinga da Marambaia, southeastern Brazil. The shrubby vegetation had a very superficial leaf litter compared to the other two vegetation types. We measured head width, body length, and femur length of the ants collected in each vegetation type. We used average head width (HW) as a proxy for body size. The shrubby-arboreal and arboreal vegetation types were assumed to represent more rugose environments than the shrubby vegetation. Leg length allometry was observed in each and all vegetation types. We did not find significant differences in body size and allometry of ant assemblage among vegetation types. Hence, the size-grain hypothesis was corroborated only for leg allometry, but it did not predict a general environmental influence on ant morphometry.

O estudo objetivou avaliar a resposta da assembleia de formigas que nidificam na interface solo-serapilheira a um gradiente de alteração ambiental. O estudo foi realizado em três ambientes com diferentes usos do solo: fragmento florestal, sistema agroflorestal (SAF) e pastagem situados em região de domínio da mata atlântica no sudeste do Brasil. Em cada ambiente foram demarcadas 10 parcelas de 1 m² e todos os ninhos de formigas encontrados foram registrados. Foram encontrados 215 ninhos (103 no fragmento florestal, 64 no sistema agroflorestal e 48 na pastagem), de 31 espécies. O número acumulado de espécies foi maior no fragmento florestal que na pastagem, mas não diferiu do SAF. A composição de espécies foi diferente entre o fragmento florestal e os outros dois ambientes. A riqueza média de espécies de formigas por parcela foi maior no fragmento florestal e menor na pastagem. A quantidade de serapilheira não foi um fator importante para as diferenças na riqueza de espécies. Atividades humanas que reduzam a heterogeneidade da vegetação alteram a composição e diminuem a riqueza de espécies das assembleias de formigas. The present study aimed at assessing the response of the assemblage of ants that nest in the soil-litter interface to a gradient of environmental change. Fieldwork was carried out in three environments under different land use regimes: a forest fragment, an agroforestry system (AFS), and a pasture, all located within the Atlantic Forest of southeastern Brazil. In each environment we marked ten 1-m² plots and recorded all ant nests found within them. We recorded 215 nests (103 in the forest, 64 in the AFS, and 48 in the pasture) of 31 species. The cumulative number of species was higher in the forest than in the pasture; the forest and the AFS differed from the pasture, but did not differ from each other. Species composition differed between the forest and the other two environments. The average species richness was high in the forest and low in the pasture. The amount of litter did not explain the differences in species richness among environments. Human activities that reduce vegetation heterogeneity change the composition and reduce the richness of the ant assemblage.

In this study a tritrophic system was evaluated to measure the contributions of the insect host density and its host plant concentration in simple and diversified habitat on the rate of parasitism. The system was composed of the plant Hyptis suaveolens, two species of agromyzid leafminers, and three morphospecies of parasitoids. The parasitism rate, patch size, and habitat complexity were found to be interdependent. If only the habitat complexity or patch size was take into account the differences in parasitism rate are not significant, although habitat diversity seemed to contribute more than the host plant concentration to increase the parasitism rate. The leaves or plants with different number of mines were equally attacked by the parasitoids. The results were representative of what happened to the leafminers at different host plant densities under the homogeneous and heterogeneous habitat condition. This work could help to reinforce the idea of the importance of the plant diversity for enhancing the biological control of the pests by the parasitoids in the managed ecosystems.Foi avaliado um sistema tritrófico para medir os efeitos da densidade de insetos minadores e a concentração da planta hospedeira em habitats simples e diversificados sobre a taxa de parasitismo. O sistema era composto pela planta Hyptis suaveolens, duas espécies de agromizídeos minadores de folhas e três morfoespécies de parasitóides. A taxa de parasitismo, tamanho da mancha e a complexidade do habitat foram interdependentes. Se levarmos em consideração apenas a complexidade ou tamanho de mancha, as diferenças na taxa de parasitismo não foram significativas, embora a diversidade de habitat pareça ter contribuido mais do que a concentração da planta hospedeira para aumentar a taxa de parasitismo. Folhas ou plantas com diferentes números de minas foram igualmente parasitadas. Nossos resultados são representativos do que acontece com insetos minadores em diferentes densidades de plantas e condição do ambiente - homogêneo ou heterogêneo. Este trabalho ajuda a reforçar a idéia de que a diversidade de plantas no sistema ajuda a aumentar o controle biológico de pragas por parasitóides.

A influência de características do habitat na abundância dos parasitóides Pseudacteon Coquillett (Diptera, Phoridae) de Solenopsis invicta Buren (Hymenoptera, Formicidae) foi estudada em um agroecossistema orgânico diversificado no sudeste do Brasil. Os parasitóides foram coletados durante 30 minutos após a perturbação de ninhos da formiga lava-pé em áreas com culturas anuais ou perenes. Foram coletados no total 228 parasitóides de quatro espécies diferentes em 61,90% dos 84 ninhos da formiga lava-pé perturbados. Pseudacteon obtusus Borgmeier foi a espécie mais abundante (70 fêmeas), seguida por Pseudacteon litoralis Borgmeier (37 fêmeas), Pseudacteon tricuspis Borgmeier (23 fêmeas) e Pseudacteon solenopsidis Schmitz (1 fêmea). Pseudacteon litoralis foi mais freqüente em ninhos presentes nas culturas perenes que anuais enquanto que P. obtusus e P. tricuspis tiveram um padrão oposto. Correlações significativamente negativas foram encontradas para as abundâncias de P. litoralis e P. obtusus com a temperatura do ar. Houve correlação significativamente positiva entre a abundância dos parasitóides e o tamanho dos ninhos da formiga lava-pé. Considerando que os forídeos são importantes inimigos naturais de S. invicta, esse estudo fornece informações para o manejo de S. invicta em agroecossistemas tropicais diversificados. The influence of habitat characteristics on the abundance of the parasitoids Pseudacteon Coquillett (Diptera, Phoridae) of Solenopsis invicta Buren (Hymenoptera, Formicidae) was studied in organic polyculture agroecosystem in southeastern of Brazil. Parasitoids were collected during 30 minutes after fire ant colonies perturbation in plots with annual or perennial crops. A total of 228 parasitoids belonging to four species were obtained in 61.90% of the 84 fire ant colonies disturbed. Pseudacteon obtusus Borgmeier was the most abundant species (70 females), followed by Pseudacteon litoralis Borgmeier (37 females), Pseudacteon tricuspis Borgmeier (23 females) and Pseudacteon solenopsidis Schmitz (1 female). Pseudacteon litoralis was more frequent on fire ant mounds in plots with perennial crops than annual crops whereas P. obtusus and P. tricuspis had an opposed pattern. Negative significant correlation was found between air temperature and P. litoralis and P. obtusus abundances. Fire ant mound size and parasitoid abundance were positively correlated. Considering that phorids are important natural enemies of S. invicta, this study provides information for the management of fire ants in tropical polyculture agroecosystem.

A influência de fatores ambientais sobre a diversidade, riqueza e abundância de formigas em comunidade de restinga foi avaliada na Marambaia, litoral sul do estado do Rio de Janeiro. As amostras foram tomadas em agosto de 2004 (inverno) e março de 2005 (verão) em três fisionomias vegetais: (1) vegetação herbácea fechada de cordão arenoso (habitat homogeneo), (2) arbustiva fechada de cordão arenoso e (3) floresta de cordão arenoso (habitats heterogeneos). Em cada formação foram medidos os seguintes atributos ambientais: temperatura e umidade do solo, cobertura do solo por serapilheira e profundidade da serapilheira. Noventa e duas espécies distribuídas em 36 gêneros e oito subfamílias foram coletadas. A densidade de espécies e a abundância variaram significativamente com a fisionomia e época de coleta; a diversidade apenas com a fisionomia. O habitat homogêneo teve menor densidade de espécies, abundância e diversidade do que os habitats heterogêneos. As duas primeiras variáveis foram positivamente correlacionadas com a profundidade da serapilheira e ambas foram maiores na amostragem de verão do que na de inverno. Houve mais espécies de Ponerinae e Ectatomminae nos ambientes mais heterogêneos, enquanto que Formicinae foi mais abundante no ambiente homogêneo. The effects of environmental factors on the richness, diversity and abundance of ants were studied in the Restinga da Marambaia, south coast of Rio de Janeiro State, Brazil. The samples were taken using pitfall traps in August/2004 (winter) and March/2005 (summer) in three different vegetation types: (1) herbaceous ridge palmoid (homogeneous habitat); (2) shrub dune thicket and (3) ridge forest (heterogeneous habitats). At each habitat a range of environmental attributes was recorded: soil temperature and humidity, percentage of soil covering by litter and litter depth. Ninety-two ant species belonging to 36 genera and eight subfamilies were recorded. Density of ant species and abundance varied significantly between habitats and seasons; ant diversity varied only between habitats. Homogeneous habitat had lower ant species density, abundance and diversity than heterogeneous habitats. The two first variables were positively correlated with litter depth and both were higher in summer than in winter samples. There were more species of Ponerinae and Ectatomminae in heterogeneous than in the homogeneous habitat, whereas the Formicinae species were more abundant in the later.

Two new species of parasitoids, Eibesfeldtphora trifurcata and Eibesfeldtphora inornata, are described. Both species were collected in Brazil. A new key is provided and illustrated for the twenty one known species.

Larvae of the leaf-miners Sceloenopla pretiosa (Baly, 1858) (Cassidinae, Sceloenoplini) and Octuroplata walkeri (Baly, 1865) (Cassidinae, Chalepini) are described and illustrated. This larval description of O. walkeri is the first for the genus Octuroplata . The larvae were collected in atlantic rain forest and reared in the laboratory. The studied larvae shown the morphological adaptations common to the highly specialized leaf-miners and the larvae pupate inside the mine. Larvae of Octuroplata walkeri is similar to Sceloenopla pretiosa and the differing characteristics are described.

How does species choice influence ecological restoration outcomes? In order to answer this question, the goal of this study was to assess the community structure and species richness of natural regeneration beneath the canopy of four native species from the Atlantic Forest (Guarea guidonia (L.) Sleumer; Inga edulis Mart; Nectandra membranacea (SW) Griseb; and, Piptadenia gonoacantha (Mart.) J.F. Macbr). The research was carried out in plantations of native tree species at the Guapiacu Ecological Reserve, in Rio de Janeiro State, Brazil. Our results pointed that abundance, basal area and species richness were significantly higher beneath Inga compared to Nectandra and Guarea. Whereas the lowest values observed in Guarea may suggest its negative effects under natural regeneration. Therefore, we highlighted that the positive or negative biological effects of tree species, instead of their simple response (mortality and initial growth), must be considered in ecological restoration projects.

There is a great number of Charaxinae (Lepidoptera: Nymphalidae) species in the tropics whose larvae feed on several plant families. However the genus Anaea is almost always associated with Croton species (Euphorbiaceae). This work describes patterns of host plant use by immature and adult abundance on different vertical strata of sympatric Anaea species in a forest of Southeastern Brazil. Quantitative samples of leaves were taken in April/1999 and May/2000 to collect eggs and larvae of four Anaea species on C.alchorneicarpus, C. floribundus and C. salutaris in a semideciduous forest. Sampled leaves were divided into three classes of plant phenological stage: saplings, shrubs and trees. The results showed that the butterfly species are segregating in host plant use on two scales: host plant species and plant phenological stages. C. alchorneicarpus was used by only one Anaea species, whereas C. floribundus was used by three species and C. salutaris by four Anaea species. There was one Anaea species concentrated on sapling, another on sapling/shrub and two others on shrub/tree leaves. Adults of Anaea were more frequent at canopy traps but there were no differences among species caught in traps at different vertical positions. This work supplements early studies on host plant use among Charaxinae species and it describes how a guild of closely related butterfly species may be organized in a complex tropical habitat. Borboletas Anaea (Lepidoptera: Charaxinae) estão freqüentemente associadas a espécies de Croton (Euphorbiaceae). Este trabalho descreve a utilização de plantas hospedeiras por uma guilda de borboletas em uma floresta do Sudeste brasileiro. Folhas de três espécies de Croton foram amostradas em 1999/2000 para a coleta de ovos e larvas de quatro espécies de Anaea. Paralelamente, foram colocadas armadilhas para adultos em duas diferentes posições verticais (1 m e 5 m) para comparação do número de indivíduos capturados entre as espécies. Os resultados demonstraram que a guilda de borboletas segrega na utilização de plantas hospedeiras em duas escalas: espécie hospedeira e estágio fenológico das plantas. Crotonalchorneicarpus foi utilizada como hospedeira apenas por A. ryphea; C. floribundus foi utilizada por três espécies de Anaea; e C. salutaris, por quatro espécies. Anaeaotrere foi mais abundante em plantas jovens, A. ryphea predominou em plantas jovens e arbustos e A. appias e A. arginussa apresentaram maiores densidades em folhas de arbustos e árvores de Croton. Os adultos de Anaea foram capturados com maior freqüência nas armadilhas postas na copa das árvores, todavia não houve diferença significativa entre as espécies. Este trabalho suplementa os dados sobre utilização de plantas hospedeiras por Charaxinae e descreve como uma guilda de borboletas proximamente aparentadas pode estar organizada em um ambiente tropical complexo.