Potential for artificial symbiosis between marine microalgae and invertebrates: II. survival of marine mollusks with the transplanted dinoflagellate Effrenium voratum (Symbiodiniaceae)

Symbiotic relationships between marine invertebrates and microalgae are well-known in cnidarians and mollusks, such as jellyfish, hydroids, and nudibranchs. To explore physiological compatibility between other mollusk species and microalgae, we injected the free-living (FL) strain of the dinoflagellate Effrenium voratum into the body of the cephalopod Octopus minor, nudibranchs Chromodoris orientalis and Dendrodoris fumata, sea snails Nassarius sp., Tectus fenestratus, and Babylonia spirata, and abalone Haliotis discus hannai and monitored the survival of these mollusks and transplanted microalga for 7 d. The transplanted E. voratum (FL) survived for 7 d inside the bodies of all mollusks except H. discus hannai. In additional experiments, the transplanted E. voratum (FL) survived for 25 and 17 d inside the bodies of C. orientalis and O. minor, respectively, until the mollusks died. Therefore, the results obtained in this study suggest that the nudibranch and cephalopod explored herein have the potential for physiological compatibility with microalgae. These findings represent an initial step toward evaluating symbiotic compatibility in novel host-symbiont systems.