RESUMO Camponotus é um dos gêneros mais especiosos e abundantes da subfamília Formicidae. O gênero é representado por formigas que se alimentam e nidificam nos mais diversos habitats de ambientes terrestres e arbóreos. Entre as espécies arborícolas de Camponotus, estão as do subgênero Dendromyrmex. Registramos, pela primeira vez, Camponotus chartifex (Smith, 1860) para o estado de Mato Grosso, Brasil, e expandimos a distribuição de Camponotus nidulans (Smith, 1860) e Camponotus apicalis (Mann, 1916), incluindo informações biológicas sobre as espécies e uma discussão sobre a amostragem de formigas arborícolas e aladas.

ABSTRACT Camponotus (Formicinae) is the most specious and abundant genus of the family Formicidae. The genus is represented by ants that both forage and nest in the most diverse terrestrial and arboreal environments. Among the arboreal species of Camponotus are those of the subgenus Dendromyrmex. We recorded, for the first time, evidence of Camponotus chartifex (Smith, 1860) in the state of Mato Grosso, Brazil, and expanded the distributions of Camponotus nidulans (Smith, 1860) and Camponotus apicalis (Mann, 1916). We include information on the biology of the species and a discussion on the sampling of arboreal and winged ants.

RESUMEN Las hormigas habitan y explotan los hábitats más variados desde el subsuelo hasta el dosel del bosque. Sin embargo, los estudios sobre la diversidad de hormigas de la vegetación son menos frecuentes en el Amazonas. En este artículo enumeramos las especies de hormigas recogidas en el sotobosque de un remanente de bosque en un paisaje del sur de la Amazonia. La lista incluye 32 especies, de las cuales tres (9 %) son nuevos registros para el estado de Mato Grosso, Brasil, siendo una de estas especies muestreadas por primera vez en Brasil.

ABSTRACT Ants inhabit and exploit the most varied habitats from the underground to the forest canopy. However, studies on the diversity of arboreal ants are less frequent in the Amazon. In this paper we list arboreal ant species sampled in understory along four transects in a forest remnant in a South Amazonian landscape. The list includes 32 species, of which three (9 %) are new records for the state of Mato Grosso, Brazil, one of these species being sampled for the first time in Brazil.

Abstract The state of Mato Grosso is the 3rd largest Brazilian state, is covered with three major Brazilian biomes, including the Pantanal, Cerrado, and Amazonia. To date, 449 ant species are recorded in literature for the state. In the present work, we documented the ants sampled along a fragmented landscape, in the municipality of Juara, in the Cerrado-Amazon transition zone in the state of Mato Grosso, Brazil. The ant species were captured with Pitfall traps installed in 20 trails with 10 traps in each (totaling 200). Our results show 151 species, belonging to 43 genera and eight subfamilies, of which 28 species were recorded for the first time in the state and five species recorded for the first time in Brazil. Most genera collected were Pheidole Westwood, 1839 (45 species) followed by Crematogaster Lund, 1831 (11 species). By highlighting species recorded for the first time in state of Mato Grosso and Brazil, we hope to encourage new discoveries and increase the general knowledge of the ant fauna of different biomes in the region.

Neste estudo nós apresentamos um novo registro de uma interação planta-animal: a relação mutualística entre a formiga especialista Myrcidris epicharis Ward, 1990 (Pseudomyrmecinae) e sua mirmecófita hospedeira Myrcia madida McVaugh (Myrtaceae). Observamos mais de 50 plantas de M. madida ocupadas por M. epicharis em ilhas e margens do rio Juruena, no município de Cotriguaçu, Estado de Mato Grosso, Brasil (Amazônia Meridional). Discutimos a possível distribuição dessa interação simbiótica através de florestas ripária da bacia do Rio Amazonas e suas conseqüências para a coevolução do sistema.

In this study we present a new record of a plant-animal interaction: the mutualistic relationship between the specialist plant-ant Myrcidris epicharis Ward, 1990 (Pseudomyrmecinae) and its myrmecophyte host Myrcia madida McVaugh (Myrtaceae). We observed more than 50 individuals of M. madida occupied by M. epicharis in islands and margins of the Juruena River, in Cotriguaçu, Mato Grosso, Brazil (Meridional Amazon). We discuss a possible distribution of this symbiotic interaction throughout all the riparian forest of the Amazon River basin and its consequence to coevolution of the system.