Colony life history of the tropical arboreal ant, Cephalotes goniodontus De Andrade, 1999

Arboreal ants are ecologically important in tropical forests, but there are few studies using DNA markers to examine their population and colony structure. Colonies of the arboreal turtle ant Cephalotes goniodontus create trail networks through the canopy of the tropical forest, in dense vegetation where it is difficult to determine how long a nest is used and how neighboring colonies partition space. We monitored 53 nest sites for up to six years and, using seven microsatellite markers, genotyped samples of workers collected at or near 41 nests over 1-4 years. We calculated average relatedness within samples collected at a given location, and between samples collected at the same location in successive years, and performed pedigree analysis to predict the number of queens that produced each sample of workers. Fifteen samples were highly related (r ≥ 0.6) from single colonies, of which 11 were monogynous and the remaining four had two queens; 19 were of intermediate relatedness (0.1 ≤ r < 0.6) with 1-6 queens, and 7 were groups of unrelated workers (r < 0.1) from at least 4 queens. Colonies persisted at the same nest site for 2-6 years. The smallest distance we found separating nests of different colonies was 16.2 m. It appears that different colonies may share foraging trails. Our study demonstrates the feasibility of using a cost-efficient genotyping method to provide information on colony structure and life history of ant species.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00040-024-00974-3.

An Epiphytic Ant-Plant Mutualism Structures Arboreal Ant Communities

Arboreal ant communities are primarily structured by interactions among ant species, food availability, and physical structures within the environment. Epiphytes are a common feature of tropical forests that can provide ants with both food and nesting space. To date, little work has examined what role epiphytic ant-plants play in structuring arboreal ant communities. We surveyed ant species inhabiting the Australian epiphytic ant-plant Myrmecodia beccarii Hook.f. (Gentianales: Rubiaceae) and how arboreal ant communities are structured in relation to M. beccarii presence on trees. Myrmecodia beccarii was inhabited by the ant Philidris cordata Smith, F. (Hymenoptera: Formicidae) on the majority of Melaleuca viridiflora Sol. Ex Gaertn. (Myrtales: Myrtaceae) trees with ant-occupied ant-plants at our two sites. Dominant arboreal ant species at both study sites exhibited discrete, nonoverlapping distributions, and C-score analysis detected an ant mosaic at one site. The distribution of P. cordata was limited by the distribution of ant-plants for both sites. Philidris cordata dominance on trees was also determined by the presence of M. beccarii occupied by P. cordata at both sites. We suggest that by providing P. cordata with nesting space M. beccarii plays a role in structuring these arboreal ant communities.