Occurrence and natural history of Myrmelachista Roger (Formicidae: Formicinae) in the Atlantic Forest of southeastern Brazil

Abstract

Information on the biology of the species in Myrmelachista remains notably scarce. The objective of this study was to report the occurrence, analyze the infl uence of canopy cover on the number of nests in twigs in the litter describe behavioral characteristics of this genus. Hand sampling was performed on trees and twigs deposited in the litter. A total of 84 nests and seven species were found. Myrmelachista ruszkii and M. catharinae were the most frequent and abundant species. In trees, most of the nests were located at the ti ps of dry twigs, and these nests were probably the source of the nests found in the litter of fragments of Atlantic Forest of southeastern Brazil. Canopy cover is associated with the number of nests that were in twigs.Key words: canopy, dense ombrophilous forest, polydomy, reproduction, tree species. RESUMENMyrmelachista es un género neotropical de hormigas arborícolas que nidifi can en cavidades de troncos y ramas. El conocimiento sobre la biología de sus especies es escaso. Este trabajo tuvo como objetivo registrar la ocurrencia, analizar la infl uencia del dosel sobre el número de nidos en ramas en la cama (mezcla de hojas, ramas y tierra) que cubre la selva, y describir las características de comportamiento de Myrmelachista. Se realizaron recolectas manuales de arbóreas y en ramas depositadas en la mezcla anterior. Se encontraron 84 nidos y siete especies Myrmelachista ruszkii y M. catharinae fueron las más frecuentes y abundantes. En las especies arbóreas la mayoría de los nidos se localizan en las extremidades secas de las ramas estos nidos fueron probablemente el origen de los nidos que se encuentran en las camas de los fragmentos de Floresta Atlántica de la región sureste brasileña. El número de nidos en ramas estaría asociado con la cobertura arbórea.Palabras clave: bosque ombrófi lo denso, dosel, especies arbóreas, polidomia, reproducción.

Ground-Dwelling and Vegetation Ant Fauna in Southern Brazilian Grasslands

“…flavidulus). Myrmelachista is considered an exclusively arboreal genus (Longino, 2006), nesting in cavities and dry twigs of living trees, and is rarely found foraging on the ground (Nakano et al, 2013;Baccaro et al, 2015). Species in this genus may also develop associations with host plants, extrafloral nectaries or associated aphids.…”

Seasonal Patterns of the Foraging Ecology of Myrmelachista arthuri Forel, 1903 (Formicidae: Formicinae)

“…However, there were no nests inside fallen twigs in the leaf litter. Similarly, in a large study of Myrmelachista species, Nakano et al (2012Nakano et al ( , 2013 did not find M. arthuri nests in fallen twigs; these authors were only able to find this species in live tree stems or in recently fallen tree stems.…”

“…Myrmelachista arthuri followed this pattern regardless of the season, although foraging was more intense in the cold/dry season. In this case, the activity pattern was influenced by season and probably related to low food availability, which causes the workers to leave the nest more often (Fowler et al, 1991;Yamamoto & Del-Claro, 2008;Belchior et al, 2012;Lima, 2013).Workers foraged less frequently in the warm/wet season, despite higher energy requirements due to increases in temperature (Lima, 2013) and a late production (Nakano et al, 2013) and greater food availability in the environment (Belchior et al, 2012).…”

“…These ants use plants as shelter and feed on extrafloral nectaries; in return, the host plant receives protection against herbivores and parasites (Frederickson & Gordon, 2009). Ants in this genus may also feed onanimal-derived proteins (Nakano et al, 2013) or honeydew from scale insects (Longino, 2006).…”

“…Myrmelachista colonies are usually big, polydomous and/or polygynous and occupy dead branches or live tree stems (Frederickson, 2005;Longino, 2006;Frederickson & Gordon, 2009;Nakano et al, 2012;Nakano et al, 2013), making it difficult to study the biology of the species. In this work, we describe how M. arthuri foraging patterns and diet vary between different seasons of the year, in addition to reporting other aspects of its natural history.…”