Light quantity controls locomotion in photosymbiotic Aiptasia

Many cnidarians engage in endosymbiotic relationships with photosynthetic microalgae in the family Symbiodiniaceae. This symbiosis is deeply integrated into the physiology of the host. Although positive phototaxis and phototropism have been reported for symbiotic cnidarians, it is currently unknown whether light quantity influences phototactic behavior. Here we tested behavior of aposymbiotic (without Symbiodiniaceae) and symbiotic (with Symbiodiniaceae) Aiptasia in a light gradient to assess presence and effect of phototactic behavior.