The genetic characterization of Myrmelachista spp. Roger (Hymenoptera: Formicidae) specimens collected in the Atlantic Forest of southeastern Brazil

Abstract

Arboreal ants of the genus Myrmelachista, which have ecologically important relationships with different vegetable species, are found exclusively in the Neotropical region. These ant species are difficult to identify, and their taxonomy remains controversial; moreover, little is known regarding their biology. The objective of the present work is to assess the genetic similarities and dissimilarities between and within Myrmelachista species, with the goal of expanding knowledge of the relationships among the taxa of this genus. Sample collection in selected regions of the dense ombrophile forest of southeastern Brazil yielded 256 nests, which were found in vegetation or among scattered twigs in the leaf litter; eight species were recorded. A total of 180 specimens were analyzed, producing 123 molecular characters. Data analyses revealed similarity relationships that allowed the examined species to be classified into the following groups: (1) Myrmelachista sp. 4, M. nodigera, M. ruszkii and M. gallicola; (2) M. catharinae and M. arthuri; (3) M. reticulata; and (4) Myrmelachista sp. 7. The study results also revealed the existence of two morphological variants of M. catharinae; M. arthuri was more closely related to one of these M. catharinae variants than to the other variant. The present work provides important information regarding genetic variation among Myrmelachista species that may contribute to interpreting the complex morphology of this genus.

Morphological differentiation between species of Myrmelachista Roger (Formicidae: Formicinae) in Atlantic Forest areas of the Alto Tietê (São Paulo)

“…Workers of M. catharinae and M. arthuri are genetically close (Nakano et al, 2014). In our analyses, these species exhibited high morphological overlap, similarly to workers from M. gallicola and M. nodigera.…”

“…In our analyses, these species exhibited high morphological overlap, similarly to workers from M. gallicola and M. nodigera. Other studies have also reported morphological (Quirán & Martinez, 2006), behavioral (Nakano et al, 2013) and genetic (Nakano et al, 2014) similarities between these species.…”

“…Genetic analysis of M. catharinae workers revealed two groups (Nakano et al, 2014), which was not confirmed by morphometry. However, males of M. catharinae were classified into two groups, which suggests some phenotypic variability retrieved in our morphometric analyses.…”

“…The species analyzed were Myrmelachista arthuri Forel, 1903, M. catharinae Mayr, 1887, M. gallicola Mayr, 1887, M. nodigera Mayr, 1887, M. reticulata Borgmeier, 1928, M. ruszkii Forel, 1903, Myrmelachista sp.4 and Myrmelachista sp.7 (Suguituru et al, 2015. A more detailed description of the collection sites, methods used, and specimen identification can be found in Nakano et al (2012Nakano et al ( , 2013Nakano et al ( , 2014.…”

“…Morphological characters of taxonomic importance are not well defined, and it is necessary to combine information from all castes (workers and reproductive ants). Nakano et al (2014) showed that some species may be separated using molecular characters, despite their high morphological similarity (Nakano, 2010). However, no detailed morphological study has been performed to evaluate species delimitation in Myrmelachista.…”