Menthol-induced bleaching rapidly and effectively provides experimental aposymbiotic sea anemones (Aiptasia sp.) for symbiosis investigations.

ABSTRACT Experimental manipulation of the symbiosis between cnidarians and photosynthetic dinoflagellates ( Symbiodinium spp.) is crucial to advancing the understanding of the cellular mechanisms involved in host–symbiont interactions, and overall coral reef ecology. The anemone Aiptasia sp. is a model for cnidarian–dinoflagellate symbiosis, and notably it can be rendered aposymbiotic (i.e. dinoflagellate-free) and re-infected with a range of Symbiodinium types. Various methods exist for generating aposymbiotic hosts; however, they can be hugely time consuming and not wholly effective. Here, we optimise a method using menthol for production of aposymbiotic Aiptasia . The menthol treatment produced aposymbiotic hosts within just 4 weeks (97–100% symbiont loss), and the condition was maintained long after treatment when anemones were held under a standard light:dark cycle. The ability of Aiptasia to form a stable symbiosis appeared to be unaffected by menthol exposure, as demonstrated by successful re-establishment of the symbiosis when anemones were experimentally re-infected. Furthermore, there was no significant impact on photosynthetic or respiratory performance of re-infected anemones.