New study reveals evolutionary cycles of ants

Researchers from the Czech Academy of Sciences (Pável Matos-Maraví and Milan Janda) led an international study that supports an old island-biogeography hypothesis. The Taxon Cycle hypothesis was coined 60 years ago by the influential biologist E.O. Wilson, who believed in the existence of cycles of evolution of ecologically successful insular taxa. The Taxon cycle hypothesis postulates that adaptation to exploit resources in species-poor habitats (e.g., coastal habitats, open grasslands, disturbed forests) is a pre-requisite to invade distant geographical areas. This expectation is better evidenced in island-like landscapes wherein geographical areas are isolated yet dispersal among them is possible (e.g., archipelagos, patches of rainforests, etc).

The study published in the journal Molecular Ecology provides a strong evidence for the biogeographical predictions of the Taxon Cycle. The authors studied ants from the Melanesian archipelago and applied molecular phylogenetic and statistical approaches to test a set of predictions, altogether informing on the role of adaptation to edge and disturbed habitats in dispersal capabilities of the ants. By using a novel biogeographical model that includes trait-dependent dispersal, the study found statistical support for the scenario of ecological shift followed by geographical range expansion, and that this repeated over millions of years.

This study offers an alternative view to island biogeography by proposing that dispersal is not neutral but is influenced by the ecology of each species. Moreover, it may be useful to understand the evolution of invasive species.

Matos-Maraví et al. (2018) Taxon Cycle predictions supported by model-based inference in Indo-Pacific trap-jaw ants (Hymenoptera: Formicidae: Odontomachus). Molecular Ecology, in Press. DOI: 10.1111/mec.14835.

Link: https://onlinelibrary.wiley.com/doi/abs/10.1111/mec.14835