Cytogenetic survey of eight ant species from the Amazon rainforest

Abstract

Even in the molecular cytogenetics era, classical cytogenetic research remains useful and can provide powerful insights about the phylogenetic relationships of several taxa, particularly those that are ultra-diverse, such as ants, which facilitate better discussions about biodiversity. In this study, we describe the karyotypes of eight ant taxa collected from Amazonian localities in French Guiana and Brazil. The chromosome numbers ranged from 2n = 18 to 68. The following chromosome numbers were observed for each organism: Azteca sp. group chartifex 2n = 28, Dolichoderus bidens (Linnaeus, 1758) 2n = 18, Gnamptogenys tortuolosa (Smith, 1858) 2n = 44, Camponotus renggeri Emery, 1894 n = 20, Pseudomyrmex unicolor (Smith, 1855) 2n = 68 and n = 34, Apterostigma sp. pilosum complex 2n = 46, Odontomachus bauri Emery, 1892 2n = 44, and Wasmannia auropunctata (Roger, 1863) 2n = 32. Three species had karyotypes similar to those from previously described species collected from the Atlantic rainorest. The karyotype of P. unicolor is reported here for the first time and showed a high chromosome number, similar to that of Pseudomyrmex gracilis. Classical cytogenetics draws attention to the need for taxonomic revision in the genera Azteca and Apterostigma and revealed aspects about chromosome evolution regarding to the polymorphism of W. auropunctata and O. bauri, as well as the heteromorphism of G. tortuolosa. The scarce information regarding ant diversity in the state of Amapá and lack of cytogenetic data from species in the northeast Amazon can hide ant biodiversity information that may be detectable with affordable cytogenetic techniques. We also discuss the importance of chromosome classification standardization using measurements.

Keywords

• Karyotype
• Chromosome evolution
• Biodiversity
• Formicidae
• Neotropics
• Taxonomy