Taxon cycle predictions supported by model‐based inference in Indo‐Pacific trap‐jaw ants (Hymenoptera: Formicidae: Odontomachus)

Abstract

Nonequilibrium dynamics and non-neutral processes, such as trait-dependent dispersal, are often missing from quantitative island biogeography models despite their potential explanatory value. One of the most influential nonequilibrium models is the taxon cycle, but it has been difficult to test its validity as a general biogeographical framework. Here, we test predictions of the taxon cycle model using six expected phylogenetic patterns and a time-calibrated phylogeny of Indo-Pacific Odontomachus (Hymenoptera: Formicidae: Ponerinae), one of the ant genera that E.O. Wilson used when first proposing the hypothesis. We used model-based inference and a newly developed trait-dependent dispersal model to jointly estimate ancestral biogeography, ecology (habitat preferences for forest interiors, vs. "marginal" habitats, such as savannahs, shorelines, disturbed areas) and the linkage between ecology and dispersal rates. We found strong evidence that habitat shifts from forest interior to open and disturbed habitats increased macroevolutionary dispersal rate. In addition, lineages occupying open and disturbed habitats can give rise to both island endemics re-occupying only forest interiors and taxa that re-expand geographical ranges. The phylogenetic predictions outlined in this study can be used in future work to evaluate the relative weights of neutral (e.g., geographical distance and area) and non-neutral (e.g., trait-dependent dispersal) processes in historical biogeography and community ecology.

Why is fruit colour so variable? Phylogenetic analyses reveal relationships between fruit‐colour evolution, biogeography and diversification

“…We also compared the likelihood of models in which dispersal is independent of fruit colour (null model) to models in which dispersal is dependent on fruit colour (specifically, red fruit). We used a trait‐based dispersal approach (Matos‐Maravi et al, ; Matzke, ) now implemented in BioGeoBEARS , version 1.1 (https://github.com/nmatzke/BioGeoBEARS). These analyses required binary (two‐state) coding of fruit colours.…”

Habitat preference modulates trans-oceanic dispersal in a terrestrial vertebrate

“…A full description, input files and results for biogeographic modelling in BIOGEOBEARS can be found in the electronic supplementary material, Data on Dryad. Simulation-inference tests of the trait-dependent dispersal model, descriptions of code unit-tests, and additional advice for researchers using the model can be found in [25,26].…”

Reconciling supertramps, great speciators and relict species with the taxon cycle stages of a large island radiation (Aves: Campephagidae)

“…The transition from stage II to III is described in metapopulation models of speciation in the presence of gene flow between populations (e.g., Farrington, Lawson, Clark, & Petren, ). Such speciation events may lead to the onset of a new cycle of expansion (Matos‐Maraví et al., ). In the last stage IV, relictualization is characterized by a gradual decline in range size and intraspecific diversity due to accumulated local extinctions, specialization (Raia et al., , Figure ) and confinement to higher elevations (Figure ).…”

“…We, therefore, expect that the signatures of taxon cycles are strongest in direct comparisons between closely related or ecologically similar sympatric species, which might interact competitively (e.g. Matos‐Maraví et al., ). Alternatively, if older species do not show strong signatures of extinction (i.e.…”