Asexual Reproduction of the Sea Anemone Exaiptasia Pallida Under Artificial Moonlight

Abstract

Many cnidarians live in symbiosis with intracellular algae (dinoflagellates from the family Symbiodiniaceae), and are provided nutrition through photosynthesis; in exchange, cnidarians provide their algal symbionts with protection from predation. In the sea anemone Exaiptasia pallida (commonly referred to as ‘Aiptasia’), a model system for coral-symbiosis studies, planula larvae produced via sexual reproduction are initially aposymbiotic (without algae) and must obtain new algal symbionts each generation. In asexual reproduction, it is possible for pedal lacerates to acquire their algal symbionts from the parent. A previous study demonstrated that artificial moonlight can affect the rate of asexual reproduction in symbiotic Aiptasia, but it is unknown how asexual reproduction in aposymbiotic Aiptasia may differ. In this study, we hypothesized that the presence of algal symbionts and artificial moonlight together may enhance asexual reproduction in Aiptasia. We found that the rate of asexual reproduction in symbiotic anemones increased under blue light (artificial moonlight) but did not change under white light and no light. Meanwhile, the rate of asexual reproduction in aposymbiotic anemones did not considerably vary under the different light conditions. This study demonstrates how host reproduction is determined by the ability of photosynthetic endosymbionts to respond to light.