Generalists are thought to adapt to a broader breadth of ecological
conditions compared to less flexible specialists. However, few studies
have systematically tested what ecological or life-history traits are
associated with organisms' ecological flexibility. Here, we used stony
corals to test the relative effects of host traits and ecological
factors on corals' flexibility to form photosymbioses with algae. We
analyzed data from 211 stony coral species to test if coral's geographic
distribution, depth range, symbiont transmission mode, or colony
morphology predict coral-algal flexibility. We report a novel positive
correlation between coral-algal flexibility and coral species'
geographic range. Symbiont transmission mode is also a predictor of
flexibility, albeit the result is less robust against sampling bias.
Coral depth range and morphology did not show significant effects. We
discuss how host-symbiont dispersal abilities, interactions, and
evolutionary history could contribute to the observed patterns and how
this finding could inform conservation efforts.