Fig. 3. Effects of light availability on the symbioticphenotype of Aiptasia.

A Representative photographs of chlorophyll fluorescence of algal symbionts in Aiptasia depending on light availability. B Symbiont density (green) and animal mortality (yellow) depending on photosynthetic active radiation (PAR) levels. Points and error bars indicate mean ± SE; the line represents the best-fitting model with corresponding confidence intervals within the tolerance range of the stable symbiosis. The R² value shows the proportion of variance explained by the model and asterisks indicate a significant effect of light availability on the response parameter (**p < 0.010). Per light condition, gross photosynthesis was quantified for 5 Aiptasia and mortality was assessed across all 30 Aiptasia. Source data are provided as a Source Data file.