Meeting Abstract
Recapitulating the full sexual life cycle of Aiptasia in the laboratory is critical for the further development of this important model system for coral biology. This should allow development of classical and molecular genetic analyses, including germ-line transformation with gene-disruption and gene-tagging constructs. We have been attempting both to improve the efficiency and predictability of laboratory spawning and to achieve the settlement and metamorphosis of the larvae thus produced. This has led to field studies at sites in Florida that have large natural populations of Aiptasia to identify natural cues and surfaces that induce settlement and metamorphosis of the larvae. Anemones were found on mollusc shells, rocks, and crustose coralline algae, and larger populations dominate mangrove roots in the Florida Keys. Glass microscope slides and ceramic tiles were deployed at these sites to collect microbial biofilms over time. Settlement assays were then conducted on natural substrata, biofilmed slides and tiles that had been in the field for 2 months, and individual bacterial strains isolated from these surfaces. The small (~100 µm diameter), translucent Aiptasia larvae were stained with neutral red to improve visualization of larvae and potential recruits on dark surfaces. Larvae from 5-14 d old were able to attach to biofilmed surfaces as early as 8 h after initial exposure and to settle by 24 h. To our knowledge, this is the first documented observation of successful settlement of Aiptasia larvae in the laboratory. To date, a single settled larva has been observed to undergo metamorphosis. We are currently attempting both to identify the exact cues associated with the surfaces that induce settlement and to obtain consistent metamorphosis.
