Insects and spiders on Acacia mangium (Fabaceae) saplings as bioindicators for the recovery of tropical degraded areas / Insetos e aranhas em plantas de Acacia mangium (Fabaceae) como bioindicadores na recuperação de área tropical degradada

Abstract Acacia mangium is a pioneer species with fast growth and frequently used in the recovery of degraded areas. The objectives were to evaluate insects and spiders, their ecological indices and interactions on A. mangium saplings in a tropical degraded area in recovering process. The experimental design was completely randomized with 24 replications, with treatments represented by the first and second years after A. mangium seedling planted. Numbers of leaves/branch, branches/sapling, and ground cover by A. mangium saplings, Hemiptera: Phenacoccus sp. and Pachycoris torridus; Hymenoptera: Tetragonisca angustula and Trigona spinipes, Brachymyrmex sp., Camponotus sp. and Cephalotes sp.; Blattodea: Nasutitermes sp. and Neuroptera: Chrysoperla sp.; abundance, species richness of pollinating insects, tending ants, and the abundance of Sternorrhyncha predators were greatest in the second year after planting. Numbers of Hemiptera: Aethalium reticulatum, Hymenoptera: Camponotus sp., Cephalotes sp., Polybia sp., T. angustula, T. spinipes, tending ants, pollinating insects, Sternorrhyncha predators and species richness of tending ants were highest on A. mangium saplings with greatest numbers of leaves or branches. The increase in the population of arthropods with ground cover by A. mangium saplings age increase indicates the positive impact by this plant on the recovery process of degraded areas.

Resumo Acacia mangium é uma espécie pioneira, de rápido crescimento e utilizada na recuperação de áreas degradadas. Os objetivos foram avaliar insetos e aranhas, seus índices ecológicos e interações com plantas de A. mangium em área tropical degradada em processo de recuperação. O delineamento experimental foi inteiramente casualizado com 24 repetições, com os tratamentos representados pelos primeiro e segundo anos após a plantio de A. mangium. Os números de folhas/galhos, galhos/plantas e cobertura do solo por plantas de A. mangium, de Hemiptera: Phenacoccus sp. e Pachycoris torridus; Hymenoptera: Tetragonisca angustula e Trigona spinipes, Brachymyrmex sp., Camponotus sp. e Cephalotes sp.; Blattodea: Nasutitermes sp. e Neuroptera: Chrysoperla sp.; a abundância, riqueza de espécies de insetos polinizadores, formigas cuidadoras e a abundância de predadores de Sternorrhyncha foram maiores no segundo ano após o plantio. Os números de Hemiptera: Aethalium reticulatum, Hymenoptera: Camponotus sp., Cephalotes sp., Polybia sp., T. angustula, T. spinipes, formigas cuidadoras, insetos polinizadores, predadores de Sternorrhyncha e a riqueza de espécies de formigas cuidadoras foram maiores em plantas de A. mangium com maior altura e número de folhas ou galhos. O aumento populacional de artrópodes e da cobertura do solo com o processo de envelhecimento das plantas de A. mangium indicam impacto positivo dessa planta na recuperação de áreas degradadas.

Insects and spiders on Acacia mangium (Fabaceae) saplings as bioindicators for the recovery of tropical degraded areas

Abstract Acacia mangium is a pioneer species with fast growth and frequently used in the recovery of degraded areas. The objectives were to evaluate insects and spiders, their ecological indices and interactions on A. mangium saplings in a tropical degraded area in recovering process. The experimental design was completely randomized with 24 replications, with treatments represented by the first and second years after A. mangium seedling planted. Numbers of leaves/branch, branches/sapling, and ground cover by A. mangium saplings, Hemiptera: Phenacoccus sp. and Pachycoris torridus; Hymenoptera: Tetragonisca angustula and Trigona spinipes, Brachymyrmex sp., Camponotus sp. and Cephalotes sp.; Blattodea: Nasutitermes sp. and Neuroptera: Chrysoperla sp.; abundance, species richness of pollinating insects, tending ants, and the abundance of Sternorrhyncha predators were greatest in the second year after planting. Numbers of Hemiptera: Aethalium reticulatum, Hymenoptera: Camponotus sp., Cephalotes sp., Polybia sp., T. angustula, T. spinipes, tending ants, pollinating insects, Sternorrhyncha predators and species richness of tending ants were highest on A. mangium saplings with greatest numbers of leaves or branches. The increase in the population of arthropods with ground cover by A. mangium saplings age increase indicates the positive impact by this plant on the recovery process of degraded areas.

Resumo Acacia mangium é uma espécie pioneira, de rápido crescimento e utilizada na recuperação de áreas degradadas. Os objetivos foram avaliar insetos e aranhas, seus índices ecológicos e interações com plantas de A. mangium em área tropical degradada em processo de recuperação. O delineamento experimental foi inteiramente casualizado com 24 repetições, com os tratamentos representados pelos primeiro e segundo anos após a plantio de A. mangium. Os números de folhas/galhos, galhos/plantas e cobertura do solo por plantas de A. mangium, de Hemiptera: Phenacoccus sp. e Pachycoris torridus; Hymenoptera: Tetragonisca angustula e Trigona spinipes, Brachymyrmex sp., Camponotus sp. e Cephalotes sp.; Blattodea: Nasutitermes sp. e Neuroptera: Chrysoperla sp.; a abundância, riqueza de espécies de insetos polinizadores, formigas cuidadoras e a abundância de predadores de Sternorrhyncha foram maiores no segundo ano após o plantio. Os números de Hemiptera: Aethalium reticulatum, Hymenoptera: Camponotus sp., Cephalotes sp., Polybia sp., T. angustula, T. spinipes, formigas cuidadoras, insetos polinizadores, predadores de Sternorrhyncha e a riqueza de espécies de formigas cuidadoras foram maiores em plantas de A. mangium com maior altura e número de folhas ou galhos. O aumento populacional de artrópodes e da cobertura do solo com o processo de envelhecimento das plantas de A. mangium indicam impacto positivo dessa planta na recuperação de áreas degradadas.

Effects of the pesticides chlorpyriphos, metsulfuron-methyl, and thiamethoxam on ant communities in wheat crop

Ants are important components of food webs in several ecosystems. In anthropic areas, they can be used as bioindicators of the environmental impacts caused by many factors or in the evaluation of the dynamics of the recovery of an area after a certain disturbance. In this context, ants can be used as bioindicators in studies on the evaluation of environmental disturbances caused by pesticide use. Thus, the present work investigated the environmental impacts caused by the application of the insecticides chlorpyriphos and thiamethoxam and the herbicide metsulfuron-methyl in the community of ants in wheat crop (Triticum aestivum L.). The data were collected by pitfall traps and Berlese funnels. A Principal Response Curve was used for a relative abundance analysis. In addition, diversity index and richness were calculated for ant communities. The presence of six families, 11 tribes, 15 genera, and 19 morphospecies of ants belonging to the guilds of fungivorous, omnivorous, and predaceous ants were observed in the soil of the wheat crop. The insecticides chlorpyriphos and thiamethoxam reduced the richness, diversity, and relative abundance of ants of all the guilds on the surface and inside the soil. The effect of the herbicide metsulfuron-methyl on the community of ants was lower than the impact of the insecticides on these insects.

Ants of Ecuador: new species records for a megadiverse country in South America

ABSTRACT Despite its small territory Ecuador hosts a remarkable biological diversity. Paradoxically, its prominent insect richness has been poorly studied and is usually underestimated in biodiversity inventories. Ants are a major component of such richness. With the aim of promoting myrmecological research, we present 20 new ant records for the country belonging to nine genera and six subfamilies. The species Tapinoma ramulorum inrectum Forel is recorded for the first time in South America. We provide brief taxonomic diagnoses and general comments for all species. Our results expand on the records of Formicidae species previously informed for Ecuador and stress the importance of scientific reference collections as biodiversity repositories.

Ant diversity sampling in the Brazilian Amazon: a comparison of litter collection and pitfall trapping / Muestreo de la diversidad de hormigas en la Amazonía brasileña: una comparación de recolección de hojarasca y trampas de caída

Abstract Introduction: Ants in tropical forests are a hyper-diverse group that plays important ecological roles. Several studies on tropical forests have used different sampling protocols to capture soil ants, making it difficult to compare responses and patterns of diversity between studies. Thus, research that compares different well-structured and standardized sampling methodologies to adequately estimate the richness of ant species in tropical forests is necessary. Objective: In this study, we examined the combination of catches with pitfall traps with and without baits and litter collections for soil ant sampling. Methods: In the fall traps, we use two baited (sardines and bananas) and one non-baited. For the manual collections (litter sampling), the litter and only the topsoil of the loose soil were collected. Results: We found that traps containing sardine baits collected a greater abundance of ants, whereas non-baited traps collected a greater richness of ant species. On the other hand, litter collections captured the largest number of exclusive species, presenting a different species composition from the pitfall traps (with and without baits). In general, baited traps showed greater abundance in more degraded locations, while manual collections and unbaited pitfalls captured more individuals in preserved environments. Conclusions: Our results provide evidence that, for accurate sampling of soil ant assemblages in tropical forests, the use of different methodologies is necessary to capture a greater diversity of species because the methods differ in effectiveness according to habitat.

Resumen Introducción: Las hormigas en los bosques tropicales son un grupo hiperdiverso que juega un papel ecológico importante. Varios estudios en los bosques tropicales han utilizado diferentes protocolos de muestreo para capturar las hormigas de suelo, lo que dificulta la comparación de respuestas y patrones de diversidad entre estudios. Por lo tanto, es necesaria una investigación que compare diferentes metodologías de muestreo bien estructuradas y estandarizadas para estimar adecuadamente la riqueza y uniformidad de las especies de hormigas en los bosques tropicales. Objetivo: En este estudio, examinamos la combinación de capturas con trampas de caída con y sin cebos y recolecciones manuales para muestreo de hormigas en el suelo. Métodos: En las trampas de otoño, utilizamos dos cebos (sardinas y plátanos) y uno sin cebo. Para las recolecciones manuales (muestreo de hojarasca), se recogió la hojarasca y solo la capa superior de suelo suelto. Resultados: Encontramos que las trampas que contenían cebos de sardina recolectaron una mayor abundancia de hormigas, mientras que las trampas sin cebo recolectaron una mayor riqueza de especies de hormigas. Por otro lado, las recolecciones de hojarasca capturaron el mayor número de especies exclusivas, presentando una composición de especies diferente a las trampas de caída (con y sin cebo). En general, las trampas con cebo mostraron mayor abundancia en lugares más degradados, mientras que las recolecciones manuales y las trampas sin cebo capturaron más individuos en ambientes preservados. Conclusiones: Nuestros resultados proporcionan evidencia de que, para un muestreo preciso de ensambles de las hormigas de suelo en los bosques tropicales, el uso de diferentes metodologías es necesario para capturar una mayor diversidad de especies, ya que los métodos difieren en la efectividad de acuerdo con el hábitat.

Medically important ants: a systematic review of the global distribution and clinical consequences of their bites and stings / Hormigas de importancia médica: revisión sistemática de su distribución global y consecuencias clínicas de sus mordeduras y picaduras

Introduction: From the medical point of view, only some ants are of special interest. Due to the diversity of ants and the growing contact with humans, it is necessary to have a better understanding of the factors and problems, which lead to adverse clinical outcomes. Objective: The aim of this study was to conduct a systematic review of published studies on ants and their impact on the medical field to synthesize fragmented knowledge and to inform the current state of this problem. Methods: A systematic literature review was conducted in Medline, EMBASE, SciELO and Google Scholar, with no time threshold. The search strategy was limited to articles published in Portuguese, English and Spanish. Eligible studies were case reports and case series that reported outcomes in humans caused by ant stings. Patient-level and study-level information was extracted. Results: The literature search yielded 1909 studies; of which 30 case reports and 16 case series reporting a total of 95 cases were included. Of these 48 patients were women (50.5 percent, and the median age was 36.1 ± 25.5 years old. The most frequently reported complications were severe pain, anaphylaxis and acute respiratory distress syndrome. The death of eighteen patients was documented (18.9 percent). Ants from the genera Solenopsis spp., Myrmecia sp., Paraponera clavata, Pachycondyla sennaarensis, Myrmecia rubra caused most of the accidents Conclusions: Severe allergic reactions caused by ants are a rare event, however, mortality can be high. An increase of ant related accidents is expected, a quick diagnosis and treatment is necessary to avoid fatalities(AU)

Introducción: Desde el punto de vista médico, solo algunas hormigas son de especial interés. Debido a la diversidad de hormigas y al creciente contacto con humanos, es necesario comprender mejor los factores y problemas que conducen a resultados clínicos adversos. Objetivo: Realizar una revisión sistemática de estudios publicados sobre las hormigas y su impacto en el campo médico para sintetizar conocimientos fragmentados e informar sobre el estado actual del problema. Métodos: Se realizó una revisión bibliográfica sistemática en Medline, EMBASE, SciELO y Google Scholar, sin límite de tiempo. La estrategia de búsqueda se limitó a artículos publicados en portugués, inglés y español. Se seleccionaron informes y series de casos sobre consecuencias de las picaduras de hormigas en humanos. Se extrajo información a nivel de paciente y a nivel de estudio. Resultados: La búsqueda bibliográfica obtuvo 1 909 estudios, de los cuales se seleccionaron 30 informes y 16 series sobre un total de 95 casos. De estos, 48 pacientes eran mujeres (50,5 por ciento) y la media de edad era 36,1 ± 25,5 años. Las complicaciones más frecuentes fueron dolor intenso, anafilaxia y síndrome de dificultad respiratoria aguda. Se documentó la muerte de 18 pacientes (18,9 por ciento). Hormigas de los géneros Solenopsis spp., Myrmecia sp., Paraponera clavata, Pachycondyla sennaarensis y Myrmecia rubra causaron la mayoría de los accidentes. Conclusiones: Las reacciones alérgicas graves provocadas por hormigas son un evento raro; sin embargo, la mortalidad puede ser alta. Se espera un incremento de los accidentes relacionados con las hormigas. Se requiere un diagnóstico y tratamiento rápidos para evitar muertes(AU)

Revisiting the ideas of trees as templates and the competition paradigm in pairwise analyses of ground-dwelling ant species occurrences in a tropical forest

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.

Invasions of four South American tramp ants: a systematic review / Invasiones de cuatro hormigas vagabundas suramericanas: una revisión sistemática

ABSTRACT The invasion and spread of four native South American ants (Hymenoptera: Formicidae) Linepithema humile, Solenopsis invicta, Wasmannia auropunctata and Paratrechina (Nylanderia) fulva all over the world, their environmental and economic impact, and intended control tactics are documented. Displacement of these invasive species is triggered by human international movement of goods, and in one case, P. fulva, a deliberately introduction as a candidate for biological control of Atta spp. and snakes. These tramp ants displace native ants, attack native birds and reptiles, protect and transport sap sucking insects, cause damage to human commodities, and are able to cause health problems to men and domestic animals. Chemical control, producing negative environmental side effects, has shown poor success and short residual effect. Current tendencies use biological control agents, the natural enemies, parasites, predators and diseases of their original range. Quarantine and eradication programs have been implemented. The success of the tramp ants involves a small size that permits hiding in all types of packing materials, their organization in societies, varied diets, and in many cases to their late detection and initial control.

RESUMEN La invasión y la diseminación en todo el mundo, de cuatro hormigas sudamericanas nativas (Hymenoptera: Formicidae) Linepithema humile, Solenopsis invicta, Wasmannia auropunctata y Paratrechina (Nylanderia) fulva, su impacto ambiental y económico y las medidas de control empleadas, es documentado. El desplazamiento involuntario, se desencadena por el transporte internacional de bienes por los humanos y, en un caso, P. fulva, incluso, se introdujo deliberadamente, como posible agente de control biológico de Atta spp. y culebras. Estas hormigas vagabundas desplazan, principalmente, a las hormigas nativas, atacan a algunos vertebrados, aves, reptiles, entre otros, protegen y transportan insectos chupadores, dañan los productos humanos y pueden causar problemas de salud a hombres y animales domésticos. El control químico, además de sus efectos secundarios negativos ambientalmente, ha tenido poco éxito y un efecto residual corto y la tendencia actual es el uso de agentes de control biológico, teniendo en cuenta, que las hormigas traídas a su nuevo ecosistema han dejado atrás a sus enemigos naturales, parásitos, depredadores y enfermedades. También, para evitar nuevas invasiones o nuevas infestaciones, se han implementado medidas especiales de cuarentena y programas de erradicación. El éxito de las hormigas vagabundas, se debe, en parte, a su pequeño tamaño, que permite que se escondan en todo tipo de productos utilizados como material de embalaje, para el movimiento de productos, a su organización social, a sus variados hábitos alimentarios y, en muchos casos, hasta a su detección tardía.

Simple does not mean poor: grasslands and forests harbor similar ant species richness and distinct composition in highlands of southern Brazil / Simples não significa pobre: campos e florestas abrigam riqueza similar e composições distintas de espécies de formiga em regiões altas do sul do Brasil

Abstract: Several studies addressed ant communities in the dense Atlantic Forest that runs along the Brazilian coast. However, comparatively little is known about the mixed forests and grasslands that occur in the southern range of the Atlantic Forest domain. In this study we performed the first standardized assessment of ants in the forest-grassland mosaic found in the highlands of the state of Santa Catarina. We aimed to investigate and compare ant richness and composition between mixed forests and grasslands in the main mountain range of south Brazil. Ants were collected in two years with ground pitfalls, tree pitfalls and litter samples. Sixty ant species were recorded, resulting in 22 new records for "Planalto Serrano" region and three for the state of Santa Catarina: Eurhopalothrix depressa, Pheidole radoszkowskii and Wasmannia williamsoni. There was significant dissimilarity in ant species composition between grasslands and forests, but no difference in ant species richness, even considering the higher number of strata in mixed forests. Similar richness and low number of arboreal species suggest that this ant community is structured similarly to temperate ones. Both habitats presented a large proportion of exclusive species. The fact that species composition between grassland and forest areas differed, coupled with the similarity in species richness between habitats and the record of new ant species for the region, calls for strong conservation efforts in grasslands of southern Brazil, which still are little protected by conservation areas.

Resumo: Diversos estudos já foram realizados com comunidades de formigas nas regiões de Floresta Ombrófila Densa que ocorrem ao longo da costa do Brasil. Comparativamente menos é conhecido sobre as Florestas Ombrófilas Mistas e campos que ocorrem na parte meridional do domínio da Mata Atlântica. Neste estudo nós realizamos o primeiro levantamento padronizado de formigas no mosaico de florestas e campos que ocorre nas regiões altas de Santa Catarina. Nosso objetivo foi investigar e comparar a riqueza e composição de espécies entre florestas e campos na principal cordilheira do sul do Brasil. Formigas foram coletadas em dois anos com armadilhas de queda no solo e nas árvores, e com amostras de serapilheira. Sessenta espécies foram registradas, constituindo 22 novos registros para a região do Planalto Serrano e três para o estado de Santa Catarina: Eurhopalothrix depressa, Pheidole radoszkowskii e Wasmannia williamsoni. A composição de espécies diferiu significativamente entre florestas e campos, mas não houve diferença em riqueza de espécies, mesmo considerando o maior número de estratos nas florestas. Riqueza similar e pequeno número de espécies arbóreas sugere que esta comunidade é estruturada de modo semelhante às comunidades de regiões temperadas. Ambos os habitats apresentaram alta proporção de espécies exclusivas. O fato de que a composição foi diferente, somado à similaridade em riqueza de espécies entre habitats e ao registro de novas espécies, indica a necessidade de maiores esforços conservacionistas nos campos do Sul do Brasil, que ainda são pouco protegidos por unidades de conservação.

Diversity of ants and mites in the diet of the Brazilian frog Chiasmocleis leucosticta (Anura: Microhylidae) / Diversidade de formigas e ácaros na dieta do anuro brasileiro Chiasmocleis leucosticta (Anura: Microhylidae)

Abstract We describe here the diet of the microhylid frog Chiasmocleis leucosticta based on the stomach contents of 72 individuals (47 males and 25 females) collected in pitfall traps at the Reserva Florestal de Morro Grande, state of São Paulo, southeastern Brazil. We identified 1,981 food items distributed in 13 prey categories of arthropods, mainly ants, mites and collembolans. Formicidae was the most abundant and frequent prey category, including 16 genera from seven subfamilies, and data on ant availability in the habitat suggest that C. leucosticta selects ants actively. The second main prey category was Acari, predominantly represented by mites of the suborder Oribatida. This is the first work identifying mites to the family level in the diet of a Microhylidae. There was no statistical difference between males and females regarding diet composition.

Resumo Descrevemos neste trabalho a dieta do anuro Chiasmocleis leucosticta, pertencente à família Microhylidae, com base no conteúdo estomacal de 72 indivíduos (47 machos e 25 fêmeas) coletados em armadilhas-de-queda na Reserva Florestal de Morro Grande, SP. Foram identificados 1981 itens alimentares, distribuídos em 13 categorias de artrópodes, especialmente formigas, ácaros e colêmbolos. Formicidae foi a categoria de presas mais abundante e frequente, incluindo 16 gêneros pertencentes a sete subfamílias. Os dados de disponibilidade de formigas no ambiente sugerem que C. leucosticta seleciona formigas ativamente. A segunda categoria de presas mais relevante foi Acari, predominantemente representada por ácaros da subordem Oribatida. Este é o primeiro trabalho que identifica os ácaros ao nível de família na dieta de um Microhylidae. Não houve diferença estatística entre machos e fêmeas quanto à composição da dieta.

Are ant assemblages of Brazilian veredas characterised by location or habitat type? / Caracterização da assembleia de formigas (Hymenoptera: Formicedae) em veredas impactadas pela monocultura de Eucaliptus

Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

O ecossistema ribeirinho do Cerrado brasileiro, é conhecido como “vereda”, e é formado em solos arenosos com altas concentrações de turfa, além de serem responsáveis pela recarga dos reservatórios dos aquíferos. Atualmente, as veredas estão sob ameaça de várias atividades humanas, especialmente a supressão da vegetação para plantio de Eucalyptus. Apesar de sua importância ecológica e elevado valor na conservação, pouco se sabe sobre os efeitos das perturbações humanas sobre a comunidade de animais. Para avaliar como que habitats em diferentes veredas e as plantações circundantes afetam a assembleia de formigas, foram selecionadas quatro “veredas” independentes, sendo duas impactadas pela monocultura de eucalipto (uma jovem e uma madura) e duas controles com a planície de inundação circundada por vegetação de cerrado. A coleta das formigas foi realizada em Maio de 2010 (estação seca) por meio de três métodos complementares, iscas atrativas, armadilhas de pitfall e coleta direta, no habitat de planície alagada, e na área circundante. Foi amostrado um total de 7.575 formigas, pertencentes a sete subfamílias, 32 gêneros e 124 espécies. A riqueza e abundância de formigas não diferiram entre as localidades “veredas”, mas sim entre os habitats. Quando impactados pela monocultura, a abundância e a riqueza diminuem nas planícies de inundação, mas os habitats de cerrado foram menos afetados. As plantações de eucalipto têm sua composição de espécies de formigas definida pela alta dominância de Pheidole sp. e Solenopsis invicta, enquanto os habitats naturais foram definidos por espécies de Camponotus e Crematogaster. Atta sexdens foi estritamente relacionada à habitats nativos de “veredas” preservadas. A monocultura de eucalipto requer grandes quantidades de água nos estágios iniciais, o que pode ter provocado a queda no nível do lençol freático nas planícies alagadas, permitindo a colonização deste habitat por espécies de formigas de hábitos hipógeos, como Labidus praedator.

Energy substrate used by workers of leaf-cutting ants during nest excavation

Energy substrate used by workers of leaf-cutting ants during nest excavation. In this study we aimed to ascertain whether leaf-cutting ant workers lose body reserves (fat or sugars) as a function of nest excavation. For each treatment, we isolated 10 workers of Atta sexdens into two experimental groups, Control (C- without excavation) and Soil (S- with excavation), which were kept for different time intervals (0, 24, 48 or 72 hours), totaling 700 tested workers. We then determined the concentration of soluble carbohydrates and total lipid content in them. The total carbohydrates were determined colorimetrically, based on the reaction between carbohydrates and sulfuric acid-phenol. For determination of lipids, the insects were immersed in organic solvent until they reached a constant weight. Our results showed that carbohydrates are consumed during nest excavation activities. In the experimental groups S24, S48 and S72, there was an average reduction of 5.82 (20.42%), 14.31 (44.96%) and 13.27 (43.96%) µ.mg-1 in soluble sugar when compared with the experimental groups that did not excavate. Furthermore, the lipids were not used during this activity. With respect to dry mass of the workers, their values were C0 = 8%, C24 = 10.4%, C48 = 9.2%, C72 = 10%, S24 = 9.2%, S48 = 8.7% and S72 = 8.5%. Our results show experimentally that the source of energy for nest excavation is carbohydrates, whereas lipids are conserved for other activities.

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius)

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius). During nest excavation, leaf-cutting ant workers undergo reduction in their body reserve, particularly carbohydrates. In order to estimate the energetic cost of digging, groups of 30 workers of the leaf-cutting ant Atta sexdens were sealed in a hermetic chamber for 24, 48 and 72 hours, with and without soil for digging, and had the CO2 concentration measured using respirometric chambers as well as volume of soil excavated (g). As expected, the worker groups that carried out soil excavation expelled more carbon dioxide than the groups that did not excavate. Therefore, a worker with body mass of 9.65 ± 1.50 mg dug in average 0.85 ± 0.27 g of soil for 24 hours, consuming ca. 0.58 ± 0.23 J. In this study, we calculate that the energetic cost of excavation per worker per day in the experimental set-up was ca. 0.58 J.

Exon-primed intron-crossing (EPIC) markers as a tool for ant phylogeography

Exon-primed intron-crossing (EPIC) markers as a tool for ant phylogeography. Due to their local abundance, diversity of adaptations and worldwide distribution, ants are a classic example of adaptive radiation. Despite this evolutionary and ecological importance, phylogeographical studies on ants have relied largely on mitochondrial markers. In this study we design and test exon-primed intron-crossing (EPIC) markers, which can be widely used to uncover ant intraspecific variation. Candidate markers were obtained through screening the available ant genomes for unlinked conserved exonic regions interspersed with introns. A subset of 15 markers was tested in vitro and showed successful amplification in several phylogenetically distant ant species. These markers represent an important step forward in ant phylogeography and population genetics, allowing for more extensive characterization of variation in ant nuclear DNA without the need to develop species-specific markers.

Ants in a hospital environment and their potential as mechanical bacterial vectors

Introduction We studied the richness and abundance of ant species, their bacteria and the bacteria isolated from patient clinical samples. Methods Ants were collected with baited traps at 64 sites in a public hospital in São Luis, State of Maranhão, Brazil. Results In total, 1,659 ants from 14 species were captured. The most frequent species were Crematogaster victima, Solenopsis saevissima, Tapinoma melanocephalum, Camponotus vittatus and Paratrechina fulva. Forty-one species of bacteria were isolated from the ants and 18 from patients. Conclusions Ants are potential vehicles for pathogenic and opportunistic bacteria, and they can represent a risk factor in nosocomial infections. .

Ant species (Hymenoptera, Formicidae) from the seasonally dry tropical forest of northeastern Brazil: a compilation from field surveys in Bahia and literature records

Ant species (Hymenoptera, Formicidae) from the seasonally dry tropical forest of northeastern Brazil: a compilation from field surveys in Bahia and literature records. The Caatingas occur predominantly in northeastern Brazil and comparatively it is the biome that received less attention than any other ecosystem in Brazil, representing the region where invertebrate groups are less known. We present here the first list of ant species of the Caatingas, compiling information from the literature, from a study of samples preserved in alcohol in the Laboratory of Entomology (Universidade Estadual de Feira de Santana), and from a field survey conducted in Milagres, Bahia, submitting standardized 1-m² samples of the leaf-litter to Winkler extractors. Summing all information, 11 subfamilies, 61 genera and 173 species (plus one subspecies) of ants are recognized in the biome. This species number does not consider morphospecies that could not be named due to the lack of reliable recent taxonomic information for some Neotropical ant genera. The list presented here for ant species of the Caatingas is therefore underestimated, but it is relevant because it allows the identification of areas to be sampled in order to improve our knowledge of the diversity of ants in this biome.

Does body size of neotropical ant species influence their recruitment speed? / O tamanho corpóreo de espécies de formigas neotropicais influencia na velocidade de recrutamento?

Ants are one of the most important animal groups in tropical forests because of its abundance and number of species. An important characteristic of the group is the eusociality, which allows the occurrence of a recruitment behavior when food resource is found. However, there are two main questions regarding this behavior: (i) the recruitment is a product of environmental or phylogenetic pressures, and (ii) the recruitment speed is related to the body size of the ant species. In this work we addressed these two questions using 17 species of neotropical ants, in the Amazonic lowland dense rain forest. According to results, recruitment behavior is related to ant size, where smaller species exhibit this trait when finding a protein resource. However, species size is not important in recruitment speed, which suggests that speed can be best explained by the type of food resources needed in the ant colony.

Formigas são um dos mais importantes grupos animais nas florestas tropicais devido a sua abundância e seu número de espécies. Uma característica importante do grupo é a eusocialidade, que permite a ocorrência do comportamento de recrutamento quando um recurso alimentar é encontrado. Entretanto, existem duas questões principais acerca desse comportamento: (i) o recrutamento é um produto de pressões ambientais ou filogenéticas, e (ii) a velocidade de recrutamento é relacionada ao tamanho corpóreo das espécies de formigas. Neste trabalho nós analisamos essas duas questões em 17 espécies de formigas neotropicais, na floresta Amazônica densa de terras baixas. De acordo com os resultados, o recrutamento é fortemente relacionado com o tamanho da formiga, sendo que espécies menores exibem essa característica quando encontram uma fonte protéica. Entretanto, o tamanho das espécies não é importante na velocidade de recrutamento, o que sugere que a velocidade de recrutamento pode ser melhor explicado pelo tipo de recursos alimentares necessários à colônia.

Antibacterial properties of contact defensive secretions in neotropical Crematogaster ants

Crematogaster ants use their contact venoms to compete with other ants. Although those venoms are used primarily as repellent and toxic secretions, they may have other functions. The present study aimed to test the antibacterial property of abdominal venom of three neotropical Crematogaster ant species (C. distans, C. pygmaea and C. rochai) against gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive (Enterococcus faecalis and Staphylococcus aureus) bacteria. Sterile filter paper was soaked with C. distans, C. pygmaea or C. rochai crude venom and placed on an agar dish that was inoculated with bacterial suspensions. The agar dish was incubated overnight at 37ºC and examined for zones of growth inhibition. For each tested venom and bacterial strain, three venom concentrations were used, with six replicates for each concentration: 1, 2 and 4 DGE (Dufour's gland equivalent). The venom of C. pygmaea, but not those of C. rochai and C. distans, inhibited the growth of all tested gram-positive and gram-negative bacterial strains. This is the first evidence of antibacterial properties of contact venoms in Crematogaster ants and it supports the claim that ant venoms are multifunctional. It is hypothesized that only C. pygmaea venom showed antibacterial activities due to its nesting habits.

Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities

Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. A first working list of ant species registered in Santa Catarina State, southern Brazil was published recently. Since then, many studies with ants have been conducted in the state. With data compiled from published studies and collections in various regions of the state, we present here an updated list of 366 species (and 17 subspecies) in 70 ant genera in Santa Catarina, along with their geographical distribution in the seven state mesoregions. Two hundred and seven species are recorded in the Oeste mesoregion, followed by Vale do Itajaí (175), Grande Florianópolis (150), Norte (60), Sul (41), Meio Oeste (23) and Planalto Serrano (12). The increase in the number of records since 1999 results from the use of recently adopted sampling methods and techniques in regions and ecosystems poorly known before, and from the availability of new tools for the identification of ants. Our study highlights the Meio Oeste, Planalto Serrano, Sul and Norte mesoregions, as well as the deciduous forest, mangrove, grassland and coastal sand dune ecosystems as priority study areas in order to attain a more complete knowledge of the ant fauna in Santa Catarina State.

Lista atualizada das espécies de formigas (Hymenoptera, Formicidae) registradas no Estado de Santa Catarina, sul do Brasil, com discussão sobre avanços e prioridades na pesquisa. Uma lista de espécies de formigas registradas em Santa Catarina foi publicada recentemente. Desde então, diversos estudos com formigas foram realizados em várias regiões do Estado. Neste trabalho, compilamos os dados de trabalhos publicados e de coletas avulsas, e apresentamos uma lista atualizada das espécies de formigas, com menção à distribuição geográfica nas sete mesorregiões de Santa Catarina. São registradas atualmente 366 espécies (e 17 subespécies) de formigas em 70 gêneros no território do Estado de Santa Catarina, sendo que a região Oeste apresenta o maior número de registros (207 espécies), seguida do Vale do Itajaí (175), Grande Florianópolis (150), Norte (60), Sul (41), Meio Oeste (23) e Planalto Serrano (12). O aumento no número de registros em relação à lista de 1999 deve-se principalmente à incorporação recente de métodos de coleta diferenciados e à realização de coletas em regiões e ecossistemas outrora subamostrados, além da disponibilidade de novas ferramentas de identificação. Nosso estudo aponta as mesorregiões Meio Oeste, Planalto Serrano, Sul e Norte, assim como os ecossistemas Florestas Estacionais Deciduais, Mangues, Campos e Restingas, como prioritárias para o aperfeiçoamento do banco de dados da mirmecofauna catarinense.

Ground-foraging ants (Hymenoptera: Formicidae) and rainfall effect on pitfall trapping in a deciduous thorn woodland (Caatinga), Northeastern Brazil

The semi-arid Caatinga is the fourth largest biome of Brazil, which biota still remains one of the most poorly known, especially with regard to invertebrate groups. In this study, a ground-foraging ant assemblage was surveyed during one year and the effect of rainfall on pitfall trapping was assessed. The study was performed in an area located in the municipality of Pentecoste (3º48’ S - 39º20’ W), in the State of Ceará. A 200m transect with 20 equidistant sampling points was established. Transect sampling was performed once a month during 12 months, over the period August 2008-August 2009. At each sampling point, a pitfall trap partially filled with a mixture of ethanol and monoethylene glycol was placed at the beginning of each month and remained in the field for seven days. 39 species belonging to six subfamilies and 19 genera, plus two unidentified species, were collected, with Pheidole (10 spp.) and Camponotus (8 spp.) being the taxa with the most species. 23 species were frequent, being found in more than 50% of the 12 transect samplings. Five species had an intermediate frequency (25 to 50%), while 13 were relatively infrequent (less than 25%). Most of the species (22) showed low occurrence, being found in less than 10% of the 240 samples (20 samples each month, during 12 months). Only five species were collected in more than 50% of the samples, those species being also responsible for most of the total abundance (number of captured individuals of all species) observed each month. The speciesaccumulation curves (observed and estimated) indicated that sampling sufficiency was attained, and that about 92% of the estimated ground-foraging ant fauna had been collected. 40 and 29 species were collected in the dry and rainy season, respectively, with monthly species richness ranging from 13 to 28. The total ant abundance showed a drastic decrease during the rainy season, and a negative linear correlation was found between rainfall and total ant abundance (R2=0.68). A similar negative linear correlation was found for species occurrences against rainfall (R2=0.71), and for mean number of species per pitfall trap against rainfall (R2=0.71). However, some species showed equal abundance, occurrence and mean number of individuals per pitfall trap in both seasons, while others showed a much higher abundance and occurrence during the rainy season. Pitfall trapping as a method to sample ground-foraging ant assemblage of the Caatinga biome and potential factors responsible for lower pitfall trap performance during rainy season are discussed. Rev. Biol. Trop. 59 (4): 1637-1650. Epub 2011 December 01.

La Caatinga semiárida es el cuarto bioma más grande de Brasil. Pese a ello, es también el bioma brasileño cuya biota continúa siendo la más pobremente estudiada, especialmente en lo que se refiere a grupos de invertebrados. En este estudio se examinó durante un año el grupo de hormigas que forrajean en el suelo de un área de Caatinga y se evaluó el efecto de la lluvia sobre las trampas de caída. El estudio se llevó a cabo en un área del municipio de Pentecoste (3º48’ S - 39º20’ W), estado de Ceará. Se estableció un transecto de 200m con 20 puntos de muestreo equidistantes. El muestreo del transecto se realizó mensualmente durante 12 meses, entre Agosto 2008-Agosto 2009. En cada punto de muestreo se colocó al principio de cada mes una trampa de caída parcialmente llena con una mezcla de etanol y monoetilenglicol y se mantuvo en el campo durante siete días. Se recogieron 39 especies pertenecientes a seis subfamilias y 19 géneros, además de dos especies sin identificar, siendo Pheidole (10 spp) y Camponotus (8 spp) los taxones con más especies. Veintitrés especies fueron frecuentes, se registraron en más del 50% de los 12 transectos muestreados. Cinco especies tuvieron una frecuencia intermedia (25 a 50%), mientras 13 fueron relativamente infrecuentes (menos del 25%). La mayoría de las especies (22) mostraron una presencia baja, encontrándose en menos del 10% de las 240 muestras (20 muestras cada mes durante 12 meses). Sólo cinco especies fueron recogidas en más del 50% de las muestras, fueron además responsables de casi toda la abundancia total (número de individuos capturados de todas las especies) mensual. Las curvas de acumulación de especies (observadas y estimadas) indicaron que se consiguió un muestreo suficiente y que se había recogido cerca del 92% de la fauna estimada de hormigas terrícolas forrajeras. Se recogieron 40 y 29 especies durante las estaciones seca y lluviosa, respectivamente, con una riqueza de especies mensual entre 13 y 28. La abundancia total de especies mostró una disminución drástica durante la estación de lluvias, y se encontró una correlación linear negativa entre la pluviosidad y la abundancia total de hormigas (R2=0.68). Una correlación linear negativa similar se encontró entre la ocurrencia de especies y la pluviosidad (R2=0.71), y entre el número medio de especies por trampa de caída y la pluviosidad (R2=0.71). Sin embargo, mientras se observó que algunas especies tenían la misma abundancia, presencia, y número medio de individuos por trampa de caída en ambas estaciones, otras tenían una abundancia y presencia mucho mayor durante la estación lluviosa. Se discute el uso de trampas de caída como método para muestrear el grupo de hormigas que forrajean en el suelo del bioma de la Caatinga, así como los factores potenciales responsables del rendimiento más bajo de las trampas de caída durante la estación lluviosa.