Abstract 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.
ABSTRACT We revise the taxonomy of species of the ant genus Cephalotes occurring in Brazil. Sixty-four species are recognized, distributed in 14 species groups. Five species are described as new: Cephalotes gabicamacho new species, Cephalotes marycorn new species, and Cephalotes monicaulyssea new species (angustus group); Cephalotes liviaprado new species (fiebrigi group); and Cephalotes mariadeandrade new species (pinelii group). The soldier and gyne of C. adolphi (angustus group), and the gyne and male of C. nilpiei (pinelii group) are described for the first time. Cephalotes marginatus is synonymized under C. atratus. The bruchi and the laminatus species groups are synonymized under fiebrigi and pusillus groups, respectively. The new species group manni is proposed, derived from the basalis species group. Distribution maps for each species in Brazil are provided. In addition, we provide an illustrated morphological glossary for the genus and illustrated identification keys for workers and soldiers for species groups and for all Brazilian species.
Abstract Piauí, a Brazilian Northeast state, has been considered one of the most important regions for the presence of new taxa in ants globally, especially considering the ecosystems’ diversity formed by the transition of the three biomes in the state, the Cerrado, Caatinga and the Atlantic Forest. Despite the recent increase in studies of ant diversity in the Neotropical region, Piauí still represents a major knowledge gap regarding its ant fauna. Therefore, this study aimed to increase the knowledge about the ant fauna of the state by generating a list of species with data obtained from the literature, online repositories and collection expeditions to the Serra da Capivara and Serra das Confusões National Parks. A total of 152 species in 52 genera and nine subfamilies were registered from 24 localities in Piauí. Fifty-eight out the 152 species recorded represent new records for the state, eight are new records for the Brazilian Northeast Region, and one consists of a new record for the country. Eleven species are here recognized as new for science. Considering the field expeditions carried out here, this work represents the first standardized study for the ant fauna of Piauí. The species list presented considerably exceeds the current number of species registered for the state so far. From the present 48 records, the number of species for Piauí raises to more than 150 with a tendency to increase with the accomplishment of future field endeavors and advances in the study of the local ants.
Abstract: Several studies have characterized and delimited subterranean ant assemblages. Soil extraction, one of the methods employed to access this fauna, employs the removal of monoliths. One of the most widely used methods for the extraction of soil sampling is called TSBF (developed by the Tropical Soil Biology and Fertility Programme). This method provides relevant data about the species associated with the soil. In the present study we characterized assemblages of subterranean ants using the TSBF method in different subtropical areas of the Neotropics. We considered two sampling designs in different localities. The first design resulted in 315 TSBF samples obtained from layers at distinct depths. The second design resulted in 270 TSBF samples and 270 epigaeic pitfall trap samples. This material was used to delimit the species that occur exclusively in the subterranean stratum (TSBF) and that are not found on the soil surface. A total of 281 species were recorded. Of these, 57 can be considered subterranean, based on their occurrence in subterranean strata. We also verified that the highest occurrence of ants was in the first 10 cm of soil depth. Due to the importance of using methods that efficiently extract the subterranean ant fauna in studies, we suggest the TSBF method should be used to sample ants or to associate this method with epigaeic pitfall traps to delimit strictly subterranean assemblages in specific community stratification studies.
Resumo: Vários estudos têm caracterizado e delimitado assembleias de formigas subterrâneas. A extração de solo, um dos métodos utilizados para amostragem dessa fala, implica na remoção de monólitos. Um dos métodos mais utilizados na extração de monólitos é chamado TSBF (desenvolvido pelo Programa Tropical Soil Biology and Fertility). Esse método fornece dados extremamente relevantes sobre as espécies associadas ao solo. No presente estudo, nós caracterizamos as assembleias de formigas subterrâneas usando o método TSBF em diferentes áreas subtropicais do Neotrópico. Utilizamos dois delineamentos amostrais distintos. O primeiro delineamento resultou em 315 amostras de TSBF obtidas a partir da estratificação do solo. O segundo resultou em 270 amostras de TSBF mais 270 provenientes de armadilhas pitfall epigeicas. Esse material foi utilizado para delimitar espécies que ocorrem exclusivamente no estrato subterrâneo (TSBF) e não são encontradas na superfície do solo. Registramos um total de 281 espécies. Destas, 57 podem ser consideradas subterrâneas (baseado na ocorrência no respectivo estrato). Também verificamos que a maior ocorrência de formigas se deu nos primeiros 10 cm de profundidade. Devido à importância do uso de métodos que coletem eficientemente formigas subterrâneas, sugerimos o uso do método TSBF em estudos de estratificação de comunidades ou sua associação a armadilhas do tipo pitfall epigeica para delimitar assembleias estritamente subterrâneas.
Abstract The state of Maranhão, located in northeastern Brazil, comprises three biomes: Amazonian, Caatinga, and the Cerrado. To date, 99 ant species have been recorded in the literature from the state. In the present work, we provide for the first time a profile of the ant fauna in the state based on data from the historical literature and Brazilian institutional collections. The updated records on ant diversity for the state of Maranhão revealed a total of 279 species, belonging to 71 genera and 10 subfamilies. In total, 180 species are recorded for the first time in the state, of which four species recorded for the first time in Brazil. In summary, apart from documenting the ant fauna of the region, these results provide a basis for further studies and may contribute to future conservation efforts for the biomes present in this complex landscape.
Abstract Despite the large number of studies investigating ant diversity in Brazilian biomes, no ant-related studies have been carried out in Campos Gerais, a grassland physiognomy in Paraná state. The present study is the first inventory of the ant fauna in one of the few conservation units protecting the Campos Gerais landscape, the Guartelá State Park (PEG). Sixty samples were collected from different habitats within PEG using pitfall traps. Qualitative samples of leaf litter were collected from forest fragments and submitted to Winkler extractors. In addition, manual qualitative sampling was carried out in the various physiognomies within the PEG. A total of 163 species was collected and sorted into 43 genera and nine subfamilies. Five genera and 28 species were recorded for the first time in the state of Paraná. Out of these, 17 species were also recorded for the first time in the Southern Region of Brazil and two were recorded for the first time to the country. The significant species richness in the PEG and the high number of new records is a strong sign of this ecosystem’s potential to reveal taxonomic novelties. These results suggest that PEG, and the Campos Gerais as a whole, should be the target of greater conservation efforts to preserve native remnants.
We describe and illustrate the venom apparatus and other morphological characters of the recently described Martialis heureka ant worker, a supposedly specialized subterranean predator which could be the sole surviving representative of a highly divergent lineage that arose near the dawn of ant diversification. M. heureka was described as the single species of a genus in the subfamily, Martialinae Rabeling and Verhaagh, known from a single worker. However because the authors had available a unique specimen, dissections and scanning electron microscopy from coated specimens were not possible. We base our study on two worker individuals collected in Manaus, AM, Brazil in 1998 and maintained in 70% alcohol since then; the ants were partially destroyed because of desiccation during transport to São Paulo and subsequent efforts to rescue them from the vial. We were able to recover two left mandibles, two pronota, one dismembered fore coxa, one meso-metapropodeal complex with the median and hind coxae and trochanters still attached, one postpetiole, two gastric tergites, the pygidium and the almost complete venom apparatus (lacking the gonostylus and anal plate). We illustrate and describe the pieces, and compare M. heureka worker morphology with other basal ant subfamilies, concluding it does merit subfamilial status.
Descrevemos e ilustramos o aparelho de ferrão e outros caracteres morfológicos da operária da formiga recentemente descrita Martialis heureka, uma suposta predadora especializada subterrânea, que pode representar o único sobrevivente de uma linhagem altamente divergente que teria surgido no início de diversificação das formigas. M. heureka foi descrita como a única espécie de um gênero da subfamília Martialinae Rabeling e Verhaagh, conhecida por uma única operária; como os autores da espécie tinham à disposição um único exemplar, dissecções e microscopia de varredura não foram possíveis. Baseamos nosso estudo em duas operárias coletadas também em Manaus, AM, Brasil, em 1998, e mantidas em via úmida desde então; estes indivíduos haviam sido parcialmente destruídos devido à dissecação durante o transporte para São Paulo e desmembrados pelos esforços subseqüentes para resgatá-los. Ilustramos, descrevemos e comparamos as peças da operária de M. heureka com outras subfamílias basais de formigas: duas mandíbulas esquerdas, dois pronotos, uma coxa anterior, um complexo meso-metapropodeal com as coxas e trocanteres medianos ainda conectados, um pós-pecíolo, dois tergitos gástricos mais o pigídio e o aparelho de ferrão quase completo (menos o gonóstilo e a placa anal). Concluimos que Martalinae merece de fato status de subfamília.
Simopelta minima (Brandão, 1989) was originally described based on four workers collected in soil samples from a small cocoa plantation in Ilhéus, state of Bahia, northeastern Brazil. In the subsequent years after the description, this cocoa plantation was eliminated and the species was then considered extinct by the Brazilian environmental institutions. The recent rediscovery of S. minima workers in subterranean pitfall trap samples from Viçosa, state of Minas Gerais, southeastern Brazil, over 1.000 km distant from type locality, suggests that the rarity and vulnerability status of some ant species may be explained by insufficient sampling of adequate microhabitats, in time and space.
Simopelta minima (Brandão, 1989) foi originalmente descrita com base em quatro operárias coletadas em amostras de solo provenientes de uma pequena plantação de cacau localizada em Ilhéus, Estado da Bahia, nordeste do Brasil. Nos anos seguintes à descrição, esta pequena plantação de cacau foi eliminada e a espécie passou a ser considerada extinta pelas instituições ambientais brasileiras. Recentemente foram coletadas operárias de Simopelta minima em amostras de armadilhas subterrâneas do tipo "pitfall", em Viçosa, Estado de Minas Gerais, sudeste do Brasil, a mais de 1.000 km de distância da localidade tipo. Esta redescoberta sugere que o status de raridade e/ou vulnerabilidade atribuído a algumas espécies de formigas pode ser explicado pela amostragem insuficiente de microhabitats adequados, no tempo e no espaço.
We propose the synonymy of the monotypic neotropical myrmicine (Basicerotini) ant genus Creightonidris Brown with Basiceros Schulz, and describe for the first time the worker and male of B. scambognathus n. comb., known thus far only by alate gynes. We also provide information on the distribution of this species, a revised diagnosis for Basiceros, and a revised key to workers and gynes of this genus. The few known data on the biology of B. scambognathus are summarized.
No presente trabalho, propomos a sinonimia do gênero monotípico neotropical de formigas mirmicíneas (Basicerotini) Creightonidris Brown sob Basiceros Schulz e descrevemos pela primeira vez a operária e o macho de Basiceros scambognathus comb. n., conhecida até agora somente por rainhas aladas. Apresentamos dados sobre a distribuição dessa espécie, uma nova diagnose para Basiceros e uma chave atualizada para identificação de operárias e gines do gênero. Os poucos dados conhecidos sobre a biologia de B. scambognathus são sumarizados.