Abstract The Cerrado biome is the second largest Brazilian biome, which has been suffering from the negative impacts on its original area. Such impacts can be measured by bioindicators such as ants. Thus, this study aimed to evaluate the diversity of ants associated with two areas of different phytophysiognomies in the Cerrado biome and an eucalyptus plantations, in Monte Carmelo - MG (18º43'29” S and 47º29'55" O). For the characterization of the ant fauna, pitfall traps were installed 10 m apart, in three distinct areas: Várzea, Cerradão (typical vegetation of the Cerrado biome) and Eucalyptus sp. plantations. Collections were carried out monthly, from January to December 2018. Eight traps per area were used, totaling 24 traps on each collection date. After 48 hours of exposure, the material collected in the traps were gathered and taken to the laboratory for sorting and subsequent identification. In this period, the greatest abundance of ants was found in the Eucalyptus area (749), followed by Várzea (291) and Cerradão (274) areas. The evaluated areas have the same ant species richness, being that seventeen species of ants were found in each area, which corroborated the rarefaction curve that identified a significant difference between areas. Higher levels of diversity and equitability (H´ = 2.07 and J´ = 0.73) were shown in Cerradão area. The Venn diagram indicated that the three areas shared 10 species of ants. In this respect, the Cerradão area presented Azteca alfari, Linepithema neotropicum, and Ectatomma opaciventre as exclusive species, while the other areas presented two species each. The indexes of diversity, equitability, and composition of the ant fauna found, characterize the Cerradão area as an ecologically more balanced environment.

Resumo O Cerrado é o segundo maior bioma brasileiro e vem sofrendo com os impactos negativos em sua área original. Tais impactos podem ser mensurados por meio de bioindicadores, dentre os quais, destacam-se as formigas. Nesse contexto, o presente estudo objetivou avaliar a diversidade de formigas associadas a duas áreas de diferentes fitofisionomias do bioma Cerrado e um plantio de eucalipto, em Monte Carmelo - MG (18º43’29” S e 47º29'55" O). Para a caracterização da mirmecofauna, foram utilizadas armadilhas de queda, instaladas a 10 m de distância entre si, no interior de três áreas distintas: Várzea e Cerradão (vegetação típica do bioma Cerrado) e um plantio de Eucalyptus sp. As coletas foram realizadas mensalmente, de janeiro a dezembro de 2018. Em cada coleta utilizaram-se oito armadilhas por área, totalizando 24 armadilhas. Após 48 horas de exposição, o material coletado nas armadilhas foi recolhido e levado ao laboratório para triagem e sequente identificação. No período do estudo, foi encontrada a maior abundância de formigas na área de Eucalipto (749), seguidas das áreas Várzea (291) e Cerradão (274). As áreas avaliadas possuem a mesma riqueza de espécies de formigas, sendo que foram encontradas 17 espécies de formigas em cada área, o que corroborou com a curva de rarefação que não identificou diferença significativa entre as áreas. A área de Cerradão apresentou maiores índices de diversidade e equitabilidade (H´ = 2,07 e J´ = 0,73). O diagrama de Venn indicou que as três áreas compartilharam 10 espécies de formigas entre si. Nesse aspecto, a área de Cerradão apresentou Azteca alfari, Linepithema neotropicum e Ectatomma opaciventre, como espécies exclusivas, enquanto as demais áreas apresentaram duas espécies cada. Os índices de diversidade, equitabilidade e composição da mirmecofauna encontrados, caracterizam a área de Cerradão como um ambiente ecologicamente mais equilibrado.

Abstract: Pteridium is a cosmopolitan genus of ferns that possess nectaries on its fronds (fern leaves), thereby attracting ants. Foliar (or extrafloral) nectaries are nectar-producing glands that are not related to pollination, but rather attract ants and other arthropods. Foliar nectaries are found in 101 fern species, belonging to 11 genera and six families. The aim of the study is to characterize the community of ants that visit the fronds of Pteridium esculentum subsp. arachnoideum, as well as daily and seasonal ant abundance in different frond development stages. The study was conducted in the Atlantic Forest of Rio de Janeiro state, Brazil. Bimonthly collections were established, where 30 expanding fronds and 30 fully expanded fronds were randomly marked. In each 1-hour shift starting at 8:30 am and ending at 5:30 pm, the fronds were observed for the presence of ants. Thirty three ant species were recorded on the Pteridium esculentum subsp. arachnoideum fronds, distributed into six subfamilies and 13 genera. The most abundant species were Solenopsis sp.1 and Ectatomma tuberculatum. Eight ant species were observed foraging the nectaries of tropical bracken fern fronds. Ectatomma tuberculatum has been observed feeding on the nectaries and patrolling the fronds. Ant activity peak was on mid-day during the rainy season. The tropical bracken fern Pteridium esculentum subsp. arachnoideum has a rich (the highest recorded until now on Pteridium species) and diverse ant community on its fronds, mainly on the expanding fronds. The presence of generalist predatory ants (Ectatomma tuberculatum and Solenopsis sp.1) during the entire study period suggests a positive interaction between ants and Pteridium esculentum subsp. arachnoideum.

Resumo: Pteridium é um gênero cosmopolita de samambaias que possui nectários em suas frondes (folhas de samambaias), atraindo formigas. Nectários foliares (ou extraflorais) são glândulas produtoras de néctar que não estão relacionadas com a polinização, mas podem atrair formigas e outros artrópodes. Nectários foliares já foram registrados em 101 espécies de samambaias, pertencentes a 11 gêneros e seis famílias. O objetivo do estudo é caracterizar a comunidade de formigas que visitam as frondes de Pteridium esculentum subsp. arachnoideum, bem como a abundância diária e sazonal das formigas em diferentes estágios foliares. O estudo foi realizado na Mata Atlântica do estado do Rio de Janeiro, Brasil. Foram estabelecidas coletas bimestrais, onde foram marcadas aleatoriamente 30 frondes em expansão e 30 frondes totalmente expandidas. Em cada turno de 1 hora com início às 8h30 e término às 17h30, as frondes marcadas foram observadas quanto à presença de formigas. Trinta e três espécies de formigas foram registradas nas frondes do Pteridium esculentum subsp. arachnoideum, distribuídas em seis subfamílias e 13 gêneros. As espécies mais abundantes foram Solenopsis sp.1 e Ectatomma tuberculatum. Foram registradas oito espécies de formigas forrageando os nectários foliares da samambaia. Ectatomma tuberculatum foi observada se alimentando nos nectários e patrulhando as frondes. As formigas tiveram o pico de atividade ao meio-dia e na estação chuvosa. A samambaia tropical Pteridium esculentum subsp. arachnoideum tem uma elevada riqueza (a maior já registrada até o momento para espécies de Pteridium) e diversidade de formigas em suas frondes, com maior frequência nas frondes não totalmente expandidas. A presença de formigas predadoras generalistas (Ectatomma tuberculatum e Solenopsis sp.1) durante todo o período de estudo sugere uma interação positiva entre as formigas e Pteridium esculentum subsp. arachnoideum.

Abstract The study area pertains to the Chocó Biogeography, one of the most biodiverse areas in the world, where around 40,000 ha of rainforest has been cleared for oil palm plantations. We surveyed the ant species' richness and diversity in four differently disturbed areas in Tumaco, Colombia, using pitfall traps and Winkler sacks. Study sites were two oil palm plantations of three- and seven- years' existence, a peach palm plantation Bactris gasipaes of 20 years, and an area of secondary forest of 10 years. A total of 93 ant species or morphospecies, comprising 31 genera in 8 subfamilies were identified. The subfamily Myrmicinae had the highest number of species (57), followed by Ponerinae (10) and Formicinae (9). The hybrid palm oil plantations harbored 46 species (7 years) and 50 species (3 years), respectively, while the peach palm plantation was composed of 53 species, and the secondary forest had 62 species. Ectatomma ruidum was the most dominant species in the oil palm plots (> 80% of specimen), but significantly less in the peach palm and secondary forest. The most species rich genera were Pheidole spp. (23) and Solenopsis spp. (13). No differences were observed in the ant species' diversity between the secondary forest and peach palm, contrasting with the significant differences between the secondary forest and the two oil palm areas. A comparison with studies in natural areas suggests that the oil palm monocultures have dramatically reduced the species' richness and that ten years of recovery does not bring back anything close to the original diversity.

Resumen El área de estudio pertenece al Chocó Biogeográfico, una de las áreas con mayor biodiversidad del mundo, donde se han talado alrededor de 40.000 ha de selva tropical para el establecimiento de palma aceitera. Se realizó un estudio de la riqueza y diversidad de las especies de hormigas en cuatro áreas perturbadas en Tumaco, Colombia, utilizando trampas de caída y sacos de Winkler. Los sitios de estudio fueron dos plantaciones de palma aceitera híbrida de tres y siete años, una plantación de palma de chontaduro Bactris gasipaes de 20 años y un área de bosque secundario de 10 diez años. Se identificaron 93 especies de hormigas o morfoespecies, distribuidas en 31 géneros y 8 subfamilias. La subfamilia Myrmicinae tuvo el mayor número de especies (57), Narváez-Vásquez et al.: Ant species diversity in secondary forest and three agricultural land uses. seguida de Ponerinae (10) y Formicinae (9). Las plantaciones de palma aceitera híbrida albergaron 46 especies (7 años) y 50 especies (3 años), respectivamente, mientras que la plantación de palma B. gasipaes presentó 53 especies y el bosque secundario 62 especies. Ectatomma ruidum fue la especie dominante en las parcelas de palma aceitera (> 80% del espécimen), pero significativamente menos abundante en la plantación de palma de chontaduro y el bosque secundario. Los géneros más numerosos en especies fueron Pheidole spp. (23) y Solenopsis spp. (13). No se observaron diferencias en la diversidad de especies de hormigas entre el bosque secundario y la palma de chontaduro, en contraste, se encontraron diferencias significativas entre el bosque secundario y las dos áreas de palma aceitera. Una comparación con estudios en áreas no perturbadas sugiere que los monocultivos de palma aceitera han reducido drásticamente la riqueza de especies y que diez años de recuperación vegetal no han establecido una diversidad similar a la original.

Resumen La diversidad, la permanencia y la actividad de los artrópodos terrestres se investigaron en las tierras bajas de la costa del Pacífico de Colombia con el objetivo de identificar posibles especies depredadoras para el barrenador de la raíz de la palma de aceite, Sagalassa valida. Se establecieron diez trampas de caída a lo largo de un transecto de 100 m en cuatro áreas: un bosque secundario, una plantación de palma de chontaduro de 20 años y dos plantaciones híbridas de palma aceitera de tres y siete años, respectivamente. Se realizaron 22 recolectas cubriendo un año entero. Todas las hormigas se identificaron a nivel de especie o morfoespecie, los otros artrópodos se identificaron hasta orden o, cuando fue posible, a nivel de familia. En total, se capturaron 50.603 artrópodos, los más abundantes fueron hormigas (37,0 %), seguidos de Collembola (35,4 %), Acari (10,6 %), Coleoptera (7,0 %) y Diptera; Hemiptera y Araneae en porcentajes casi iguales (2,5 %). Los ortópteros (92 % Gryllidae) estaban presentes en todas las recolectas, siempre en números bajos. El mayor número de hormigas se registró en los transectos de palma aceitera; Diptera, Hemiptera y Orthoptera fueron más numerosos en el bosque secundario; Acari, Araneae y Collembola en el transecto de palma aceitera. Ectatomma ruidum fue la especie de hormiga dominante (84,9 % de todos los especímenes) y estuvo ausente en solo 20 de las 880 capturas. El segundo género de hormigas más frecuente fue el de las legionarias con dos especies, Labidus praedator y L. coecus. Las precipitaciones, incluso las inundaciones de toda el área, y la temperatura no explicaron satisfactoriamente la variabilidad en las capturas de ningún grupo taxonómico. Se concluye que E. ruidum podría ser el depredador que proporcione control del barrenador de la raíz y se recomiendan estudios adicionales sobre su eficiencia.

Abstract Diversity, permanence, and activity of terrestrial arthropods were investigated in four areas of different land use in the lowlands of the Pacific coast of Colombia with the aim to identify potential predator species for the palm root borer, Sagalassa valida. Ten pitfall traps were established along a 100 m transect in four areas: a secondary forest, a 20 year.-old peach palm plantation, and two hybrid oil palm plantations of three and seven years of age, respectively. Twenty-two collections were made covering a whole year. All ants were identified to species or morphospecies level, the other arthropods to order or where possible to family level. In total, 50,603 arthropods were captured, the most abundant were ants (37.0 %), followed by Collembola (35.4 %), Acari (10.6 %), Coleoptera (7.0 %) and Diptera, Hemiptera and Araneae in almost equal numbers (around 2.5 %). Orthoptera (92 % Gryllidae) were present in all collections, always at low numbers. The highest number of ants were recorded in the oil palm transects; Diptera, Hemiptera and Orthoptera were more numerous in the secondary forest, Acari, Araneae and Collembola in the palm transects. Ectatomma ruidum was by far the dominant ant species (84.9 % of all specimens) and absent from only 20 of the 880 captures. The second most frequent ant genus were army ants with two species, Labidus praedator and L. coecus. Rainfall, even area-wide flooding, and temperature did not explain variability in captures of any taxonomic group satisfactorily. We conclude that E. ruidum might be the predator to provide control of the root borer and recommend further studies on its efficiency.

ResumenLa dispersión de semillas es un proceso clave en el restablecimiento de la vegetación en áreas rehabilitadas. El objetivo de este trabajo fue determinar la contribución de las hormigas Ectatomma ruidum y Pheidole fallax en la dispersión y germinación de semillas en áreas rehabilitadas en la mina de carbón del Cerrejón, Colombia. En cada área se instalaron cuatro parcelas de 6 x 40 m, donde se contó el número de nidos por especie y se midió la distancia entre los nidos más próximo de cada especie. De los nidos contabilizados cinco nidos fueron seleccionados para la extracción de semillas, por cada nido extraído se tomó un control. Un total de 295 nidos fueron contabilizados, 59 para la época seca y 236 para la época de lluvia, 84 pertenecían a P. fallax y 211 a E. ruidum. Un total de 21 304 semillas fueron encontradas en los nidos y suelos control, 19 349 fueron obtenidas de los nidos y basureros de P. fallax y 318 en nidos de E. ruidum, en el suelo control se hallaron 597 semillas. El número de semillas extraídas en los nidos fue significativamente mayor a la de los controles. El número de semillas removidas por P. fallax presentó diferencias significativas respecto a las removidas por E. ruidum. El porcentaje de germinación en los nidos fue mayor que en los controles, en el caso de P. fallax, el porcentaje de germinación fue bajo en los controles y alto tanto en los basureros como los nidos. Nuestros resultados sugieren que E. ruidum y P. fallax podrían contribuir a la dispersión de las semillas y al restablecimiento de la vegetación en las áreas donde se encuentran, lo cual es un aporte significativo para la rehabilitación de las áreas degradas por la minería.

AbstractSeed dispersal is a key process in the re-establishment of vegetation on reclaimed lands. The aim of this study was to determine the contributions of the ant species Ectatomma ruidum and Pheidole fallax to seed dispersal and germination on reclaimed lands in the Cerrejón coal mine, Colombia. Four 6 x 40 m plots were installed in each area, in which the number of nests by species was counted and distances between closest nests of each species were measured. Five of the nests counted were chosen for seed extraction, and a nearby control sample was taken from each nest. In total, 295 nests were counted: 59 nests during the dry season and 236 nests during the rainy season, of which 84 belonged to P. fallax and 211 belonged to E. ruidum. A total of 21 304 seeds were found in nests and control samples, of which 19 349 were obtained from P. fallax nest refuse, and 318 were obtained from E. ruidum nests; 597 seeds were found in control samples. The number of seeds extracted from nests was significantly higher than the number of seeds removed from control samples. There was a significant difference between the number of seeds removed by P. fallax and the number of seeds removed by E. ruidum. The seed germination percentage from nests was higher than the percentage from seeds in control samples. In the case of P. fallax, the germination percentage was lower in control samples and higher in nests and refuse. The results suggest that the ant species E. ruidum and P. fallax may contribute to seed dispersal and re-establishment of vegetation in areas where they were found. These ants may thus significantly contribute to restoration processes in areas degraded by mining.

Este trabajo compila registros publicados (1991) y no publicados (2006) sobre las especies de hormigas del PNN Gorgona y aporta nuevos registros de especies recolectadas en 2010. Se recopiló información de 15 diferentes sitios de isla Gorgona (13.82km²), incluyendo la pequeña isla de Gorgonilla (0.4899km²). Los métodos de recolecta incluyeron trampas de caída, cebos de atún, sacos Winkler, trampas Malaise, red entomológica y captura directa. El inventario de hormigas de suelo y sotobosque resultó en 107 especies y morfoespecies, 46 géneros y 12 subfamilias. Myrmicinae reunió la mayor riqueza (37 especies) seguida de Ponerinae (27) y Formicinae (12). Los géneros más ricos fueron Pachycondyla (15 especies), Camponotus (nueve) y Pheidole (ocho), mientras que 30 géneros solo presentaron una especie. Doce especies fueron muy comunes: Azteca sp., Atta cephalotes, Camponotus sericeiventris, Eciton vagans, Ectatomma goninion, Gnamptogenys annulata, Odontomachus bauri, Pachycondyla bugabensis, P. harpax, P. verenae, Paraponera clavata y Wasmannia auropunctata. En comparación con otras islas neotropicales, Gorgona tiene un número sorprendentemente elevado de especies de hormigas, ninguna de ellas invasivas. Por tanto, estos resultados sugieren que, mecanismos ecológicos y procesos de recuperación natural en el ecosistema han generado disponibilidad de microhábitats permitiendo la coexistencia una gran riqueza de especies.

Soil ant species in Gorgona Island, Colombian Pacific. Gorgona is one of the two insular areas of the Colombian tropical rain forest at the Pacific and is amongst the most diverse biogeographic regions of the world, the Choco. This study compiles information on ant species from published (1991) and unpublished (2006) studies and provides new records for ant species collected in 2010. Ants were sampled and information was obtained from 15 sites in Gorgona island (13.82km²), including the Gorgonilla atoll (0.49km²). Collecting methods included pitfall traps, tuna baits, mini-Winkler extraction of leaf litter, Malaise traps, entomological net and direct search. The soil and understory ant inventory resulted in 107 ant species and morphospecies, 46 genera in 12 subfamilies. Myrmicinae held the highest species richness (37 species), followed by Ponerinae (27) and Formicinae (12). The richest genera were Pachycondyla (15 species), Camponotus (nine) and Pheidole (eight), while 30 genera were represented by a single species. Twelve species were very common (both in distribution and time): Azteca sp., Atta cephalotes, Camponotus sericeiventris, Eciton vagans, Ectatomma goninion, Gnamptogenys annulata, Odontomachus bauri, Pachycondyla bugabensis, P. harpax, P. verenae, Paraponera clavata and Wasmannia auropunctata. Direct search was the most efficient method to collect diferent species and was responsible for 52% of the total species found. Compared to other Neotropical islands, Gorgona holds a suprisingly high number of ant species, none of them invasive. The invasive Monomorium floricola, which was collected 20 years ago, was not found in 2010. These evidences suggest that ecological mechanisms and natural recovery processes in the ecosystem have generated microhabitats allowing their coexistence. Rev. Biol. Trop. 62 (Suppl. 1): 265-276. Epub 2014 February 01.

Foraging strategies of the ant Ectatomma vizottoi (Hymenoptera, Formicidae). Foraging activity may be limited by temperature, humidity, radiation, wind, and other abiotic factors, all of which can affect energy costs during foraging. Ectatomma vizottoi's biology has only recently been studied, and no detailed information is available on its foraging patterns or diet in the field. For this reason, and because foraging activity is an important part of the ecological success of social insects, the present study aimed to investigate E. vizottoi's foraging strategies and dietary habits. First, we determined how abiotic factors constrained E. vizottoi's foraging patterns in the field by monitoring the foraging activity of 16 colonies on eight different days across two seasons. Second, we characterized E. vizottoi's diet by monitoring another set of 26 colonies during peak foraging activity. Our results show that E. vizottoi has foraging strategies that are similar to those of congeneric species. In spite of having a low efficiency index, colonies adopted strategies that allowed them to successfully obtain food resources while avoiding adverse conditions. These strategies included preying on other ant species, a foraging tactic that could arise if a wide variety of food items are not available in the environment or if E. vizottoi simply prefers, regardless of resource availability, to prey on other invertebrates and especially on other ant species.

Espécies de Mansoa são denominadas de "cipó-d'alho", por exalarem odor de alho das partes vegetativas e reprodutivas. Contudo, dados sobre morfologia e distribuição das estruturas secretoras presentes em Mansoa são escassos e ausentes para M. standleyi. O presente trabalho objetivou caracterizar a ocorrência e morfologia das estruturas secretoras do eixo vegetativo aéreo de M. standleyi. Para tanto, amostras da lâmina foliolar e de regiões nodais foram fixadas e submetidas às técnicas histológicas e de microscopia eletrônica de varredura. Testes histoquímicos, com os respectivos controles foram aplicados nas estruturas secretoras em fase secretora. Indivíduos de formigas e moscas, que visitavam a espécie foram amostrados, preservados e identificados por entomólogo. As estruturas secretoras do eixo vegetativo aéreo de M. standleyi estão representadas por tricomas glandulares dos tipos pateliformes e peltados. Todos com desenvolvimento assincrônico e presentes nas regiões nodais e lâmina foliolar, principalmente nas partes mais jovens. Nas regiões nodais, os tricomas formam um complexo secretor e, na lâmina foliolar, estão dispersos. As análises histoquímicas revelaram que os tricomas pateliformes são de fato nectários extraflorais e que os tricomas peltados, apresentam uma fração de alcaloides. Os visitantes das glândulas nodais correspondem a formigas Crematogaster (Formicidae) e Ectatomma brunea (Vespoidea, Formicidae) e moscas Oxysarcodexia (Sarcophagidae, subfamília Utitidae (Ulidiidae). Mansoa standleyi possui as estruturas secretoras do eixo vegetativo aéreo semelhantes às citadas pela literatura para Bignoniaceae, sendo esta a primeira vez, que um nectário extrafloral é descrito para a espécie.

Species of Mansoa are called "cipó-d'alho" because of the smell of garlic that wafts from their vegetative and reproductive parts. Since data on the morphology and occurrence of their secretory structures are scarce and even absent for M. standleyi, the present work characterizes the distribution and morphology of such structures in the vegetative aerial axis of the latter. To do so, samples of the leaf blade and of nodal regions were fixed and examined using histological and scanning electron microscope techniques. Histochemical tests with appropriate controls were carried out on the secretory structures during the secretory phase. Fly and ant individuals that visit the species were sampled, preserved and identified by an entomologist. The secretory structures of the vegetative aerial axis of M. standleyi are peltate and patelliform glandular trichomes. All develop asynchronously and are present in the nodal regions and leaf blade, mainly in their youngest parts. Trichomes form a secretory complex in the nodal regions while they are scattered in the leaf blade. Histochemical analyses revealed that the cupulate and patelliform trichomes are extrafloral nectaries and that the peltate ones present an alkaloid fraction. The visitors of the nodal glands are ants Crematogaster (Formicidae) and Ectatomma brunea (Vespoidea, Formicidae) and flies Oxysarcodexia (Sarcophagidae, subfamily Utitidae [Ulidiidae]). The secretory structures of the vegetative aerial axis of Mansoa standleyi are similar to those reported for Bignoniaceae. An extrafloral nectary is described for M. standleyi for the first time.

We studied the abundance, richness and composition of hunting ants and their variation in production systems in department of Caquetá-Colombia, 27 farms were selected in three productive systems (agroforestry, silvopastoral and traditional), in this nine kinds of soil uses were identified. The proportions of clean pasture, agroforestry and old stubble contributed most to differentiating the systems. Five points were sampled per farm using four different methods for sampling ants (TSBF, formalin soil washing, screening of litter and direct search). A total of 280 organisms was collected, corresponding to nine genera and 35 species, belonging to the subfamilies Ectatomminae, Paraponerinae and Ponerinae. Pachycondyla was the most diverse genus (13 species). The abundance of ants was directly correlated with species richness and the number of exclusive species. The highest richness was observed in the agroforestry (24 species), followed by silvopastoral (19) and the lowest in traditional (8). Five species were common in the three systems and seven species marked the most differences in composition between systems (this was: Ectatomma ruidum, Hypoponera sp.1 and sp.4, Odontomachus haematodus, O. brunneus and Pachycondyla constricta). The species Odontomachus brunneus was indicator for the traditional system and Paraponera clavata was in silvopastoral system. Direct search was the most efficient method to sample ants in the Colombian Amazon foothills.

Para conocer la abundancia, riqueza y composición de hormigas cazadoras y su variación en los sistemas productivos del departamento de Caquetá, se seleccionaron 27 fincas representativas de tres ventanas (agroforestal, silvopastoril y tradicional), en las cuales se identificaron hasta nueve clases de usos del suelo. Las proporciones dedicadas a pastos limpios, agroforestales y rastrojos viejos, fueron las que más contribuyeron a diferenciar las ventanas. Se muestrearon cinco puntos por finca mediante cuatro métodos para captura de hormigas (TSBF, lavado de suelo con formol, escrutinio de hojarasca y búsqueda directa). De un total de 280 individuos se determinaron nueve géneros y 35 especies de las subfamilias Ectatomminae, Paraponerinae y Ponerinae; el género más diverso fue Pachycondyla con 13 especies. La abundancia de hormigas se correlacionó directamente con la riqueza de especies y con el número de especies exclusivas. La riqueza fue mayor en la ventana agroforestal (24 especies), seguida de la silvopastoril (19) y de la tradicional (8). Cinco especies fueron comunes a las tres ventanas y siete especies (Ectatomma ruidum, Hypoponera sp.1 y sp.4, Odontomachus haematodus, O. brunneus y Pachycondyla constricta) marcaron las diferencias en composición. Odontomachus brunneus resultó indicadora para la ventana tradicional y Paraponera clavata para la ventana silvopastoril. La búsqueda directa fue el método más eficiente para muestrear hormigas cazadoras en el piedemonte amazónico.

The occurrence of the defensive technique of "death feigning" in the ponerine ant Ectatomma ruidum in Mexico is by first time reported.

In order to determine the specific composition of cadaverous arthropod fauna associated to different decomposing vertebrate substrates, we studied the carrion arthropods that feed on outdoor carcasses in San Juan province, Argentina. Arthropods were collected on animal and human remains in the field and on carcasses of domestic pig placed outdoors under controlled conditions. Forty species of carrion arthropods belonging to four orders and 15 families were recorded for the first time in this province. We present the first record of forensic fauna in Argentina of the necrophagous species Megelenophorus americanus (Coleoptera: Tenebrionidae) and three necrophilous species: Polybia ruficeps (Hymenoptera: Vespidae), Pheidole bergi (Hymenoptera: Formicidae, Myrmicinae) and Ectatoma brunneum (Hymenoptera: Formicidae, Ponerinae). Eighteen necrophagous, 18 necrophilous, one omnivorous and six adventitious species are listed on seven different cadaverous vertebrate substrates. We provide new distribution records for 18 insect species. Winter seasonality of Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) is also confirmed in this study.

En el presente trabajo se estudiaron los artrópodos carroñeros que acudieron a cadáveres de vertebrados al aire libre en la provincia de San Juan, Argentina. El objetivo fue inventariar la composición específica de la artropodofauna cadavérica, asociada a diferentes sustratos de vertebrados en descomposición. Se colectaron muestras de artrópodos sobre restos animales y humanos en condiciones de campo y sobre cadáveres de cerdos domésticos colocados al aire libre bajo condiciones controladas. Se registraron, por primera vez para la provincia de San Juan, 40 especies de artropodofauna tanatológica incluidas en cuatro órdenes y 15 familias. Se incorpora, como primera cita para la fauna forense argentina, un necrófago: Megelenophorus americanus Lacordaire (Coleoptera: Tenebrionidae), y tres necrófilas: Polybia ruficeps Schrottky (Hymenoptera: Vespidae), Pheidole bergi Mayr (Hymenoptera, Formicidae, Myrmicinae) y Ectatomma brunneum Smith (Hymenoptera, Formicidae, Ponerinae). Se citan 18 especies necrófagas, 18 necrófilas, una omnívora y seis oportunistas sobre siete diferentes sustratos cadavéricos de vertebrados. Se brindan nuevos registros de distribución de 18 especies de insectos. Se confirma la estacionalidad invernal de Callíphora vicina Robineau-Desvoidy (Diptera: Calliphoridae).

O presente estudo teve como objetivo avaliar o efeito do turno de coleta (dia e noite) na composição faunística de formigas epigéicas visitantes de iscas em áreas plantadas por Eucalyptus cloezina (Myrtaceae) e de vegetação nativa, cerrado. As coletas foram realizadas na Fazenda Boa Vista, Mannesmann Fi - El Florestal Ltda, localizada em Paineiras, MG. Foram coletadas 18 unidades amostrais: 12 em área com eucalipto e seis em área de cerrado. Cada unidade amostral foi composta de três parcelas (25 x 35 m cada), sendo que, em cada uma delas, foram distribuídas 34 iscas em grade, de 5 m em 5 m. Cada unidade amostral foi amostrada durante o dia e durante a noite. Os resultados revelaram que tanto o tipo de vegetação (cerrado e eucalipto), quanto o turno de coleta (dia e noite) influenciaram significativamente a fauna de formigas epigéicas. A ordenação (DCA) indica que o efeito dia e noite foi mais importante para a estruturação das diferentes comunidades do que o efeito da vegetação. Brachymyrmex sp.1, Brachymyrmex sp.2, Camponotus crassus-Mayr, Camponotus rufipes-(Fabricius), Cephalotes pusillus-(Klug) e Ectatomma brunneum Smith foram as espécies indicadoras do turno diurno, enquanto que Camponotus renggeri-Emery, Camponotus atriceps-(Smith), Camponotus melanoticus-Emery e Paratrechina sp. 1 foram indicadoras do turno noturno.

This study aimed at evaluating the effect of collect time (day and night) on ant fauna attracted to baits in areas of Eucalyptus cloeziana (Myrtaceae) and cerrado. The ants were collected in Fazenda Boa Vista, Mannesmann Fi - El Florestal Ltda, Paineiras, Minas Gerais State. Eigthteen sample units were collected: 12 in E. cloezina and six in cerrado. Each sample unit consisted of three plots (25 x 35 m each). The plot consisted of 34 baits distributed in a grid pattern at 5 m intervals. The sampling was carried out in the diurnal and nocturnal period. The results obtained revealed that both type of vegetation (cerrado x Eucalyptus) and the collect time (day x night) had a significative influence on the epigaeic ant fauna. The ordination (DCA) indicated that collect time effect was more important to fauna structuration than the vegetation effect. Brachymyrmex sp.1, Brachymyrmex sp.2, Camponotus crassus Mayr, Camponotus rufipes (Fabricius), Cephalotes pusillus (Klug) and Ectatomma brunneum Smith were indicator species of nocturnal period, and Camponotus renggeri-Emery, Camponotus atriceps (Smith), Camponotus melanoticus Emery and Paratrechina sp.1 were indicators of nocturnal period.

Para descrever o padrão de construção e ocupação dos ninhos de Ectatomma vizottoi, foram escavados oito ninhos durante o período de novembro de 2004 a agosto de 2006, em Dourados-MS. Os orifícios de entrada ou saída dos ninhos desta espécie possuem formato elipsóide, com acesso a um túnel alargado, similar a uma antecâmara, a qual é conectada a câmaras mais profundas do ninho. Os ninhos podem alcançar até 360,0 cm de profundidade, e apresentam de três a dez câmaras. São construídos independentemente de raízes de plantas, e o solo de seus túneis e câmaras é compactado, apresentando compartimentos específicos para depósitos de detritos da colônia. O aumento da densidade de formigas conduz a um aumento do número de câmaras, bem como da profundidade do ninho, mantendo, entretanto, um volume médio para o mesmo, evidenciando um padrão para o tamanho das câmaras dos ninhos.

The construction pattern and occupancy of Ectatomma vizottoi was described, during November 2004-August 2006 period, in Dourados, state of Mato Grosso do Sul by excavation of eight nests. The entrance openings, or exit, have an ellipsoid shape and lead to a wide tunnel, similar to a hall, which is connected to other deeper chambers in the nest. The nests reach up to 360 cm deep and contain three to ten chambers. Nests are constructed independently of plants and roots presence, and the soil of the tunnels and chambers are compacted, with specific compartments for colony deposit of detritus. The increase of the ant density led to an increase in nest depth and number of chambers, maintaining an average nest volume, which indicates a standard size for nest chambers.

A riqueza de formigas de capões do Pantanal brasileiro foi amostrada e relacionada com a complexidade estrutural das áreas. As formigas foram coletadas com armadilhas de solo do tipo pitfall em 28 capões na Fazenda Rio Negro, Município de Aquidauana, MS. A complexidade estrutural dos capões foi avaliada através de estimativa da densidade da vegetação e da espessura da serapilheira próximo às armadilhas. Setenta e uma espécies foram encontradas, pertencentes a 26 gêneros e sete subfamílias, das quais Ectatomma edentatum Roger (Formicidae: Ectatomminae) e uma espécie de Pheidole foram as mais freqüentes. Somente foi encontrada relação positiva entre a riqueza da comunidade de formigas e a densidade da vegetação herbácea, corroborando a idéia de que a heterogeneidade do ambiente é um fator determinante para a coexistência e diminuição de competição entre espécies.

Species richness of epigeic ants was surveyed in forest islands named capões of Brazilian Pantanal and related with their structural complexity. The ants were collected using pitfall traps in 28 capões from Rio Negro Farm, in Aquidauana municipality, Mato-Grosso do Sul state, Brazil. The structural complexity of capões was evaluated by measuring vegetation density and litter quantity near the pit-fall traps. Seventy-one species, distributed in 26 genera and seven sub-families were found. Ectatomma edentatum Roger (Formicidae: Ectatomminae) and one species of Pheidole were the most frequent species. Species richness was positively correlated only with herbaceous vegetation density of capões, supporting the idea that the increase in environmental heterogeneity diminishes species competition, allowing species co-occurrence.

Este estudo descreve a fauna de insetos predadores, parasitóides e formigas associada a pulgões em couve (Brassica oleracea L. var. acephala D.C.), cultivada em sistema orgânico. O pulgão foi identificado como Lipaphis pseudobrassicae Davis, sendo este o primeiro registro da espécie atacando couve no Brasil. Parasitismo primário por Diaeretiella sp. e Aphidius sp. e hiperparasitismo por Aphydencyrtus sp., Alloxysta sp., Pachyneuron sp. e Syrphophagus sp. foram observados. Vinte espécies de Coccinellidae foram coletadas, sendo que oito delas foram observadas, tanto na fase adulta como larval, atacando o pulgão: Hyperaspis (Hyperaspis) festiva Mulsant, que foi a mais abundante (72,5% do total de insetos predadores obtidos), Cycloneda sanguinea (L.), Eriopis connexa Germar, Coleomegilla maculata DeGeer, Hippodamia convergens Guérin, Heterodiomus sp., Scymnus (Pullus) sp.1 e Scymnus (Pullus) sp.2. Larvas de Syrphidae afidófagas coletadas nas folhas de couve infestadas por L. pseudobrassicae pertencem às espécies Allograpta exotica (Wiedemann) e Ocyptamus gastrostactus (Wiedemann). Larvas e pupas de Syrphidae foram parasitadas por Pachyneuron sp., Syrphophagus sp. e Diplazon laetatorius Fabricius. Larvas de Chrysopodes sp. foram observadas alimentando-se de L. pseudobrassicae. Espécies de formigas associadas às colônias desse pulgão foram Ectatomma quadridens Fabricius e Pheidole sp.

This study describes the fauna of predator insects, parasitoids and ants associated with aphids on kale (Brassica oleracea L. var. acephala D.C.) in organic system. The aphid was identified as Lipaphis pseudobrassicae Davis, and this is the first record of the species attacking kale in Brazil. Primary parasitism by Diaeretiella sp. and Aphidius sp. and hyperparasitism by Aphydencyrtus sp., Alloxysta sp., Pachyneuron sp. and Syrphophagus sp. were observed. Twenty species of Coccinellidae were collected, and eight of them were observed in adult and larval stages attacking the aphid: Hyperaspis (Hyperaspis) festiva Mulsant, which was the most abundant (72.5% of all predator insects obtained), Cycloneda sanguinea (L.), Eriopis connexa Germar, Coleomegilla maculata DeGeer, Hippodamia convergens Guérin, Heterodiomus sp., Scymnus (Pullus) sp.1 and Scymnus (Pullus) sp.2. Aphidophagous Syrphidae larvae collected on leaves of kale infested by L. pseudobrassicae belong to the species Allograpta exotica (Wiedemann) and Ocyptamus gastrostactus (Wiedemann). Larvae and pupae of Syrphidae were parasitized by Pachyneuron sp., Syrphophagus sp. and Diplazon laetatorius Fabricius. Larvae of Chrysopodes sp. were observed feeding on L. pseudobrassicae. Species of ants associated with the colony of this aphid were Ectatomma quadridens Fabricius and Pheidole sp.