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<\/div>Clownfish and anemones have a symbiotic relationship<\/p>\n
wildestanimal\/Getty Images<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
The secret\u2019s in the snot. Chemical changes in the mucus that coats a clownfish\u2019s body can blunt the sting of its symbiotic anemone partner.<\/p>\n
Researchers have long suspected that something special about the mucus of clownfish<\/a>, also known as anemonefish, protects them from the microscopic venomous barbs<\/a> of an anemone\u2019s tentacles. But the precise mechanism remained a mystery, says Karen Burke da Silva<\/a> at Flinders University in Australia.<\/p>\n To investigate, she and her colleagues raised orange clownfish (Amphiprion percula<\/em>) and bubble-tip anemones (Entacmaea quadricolor<\/em>) in the lab. Some of the fish and anemones were paired together, while others lived separately. The team took mucus samples from the fish at various times before and after they acclimated to their anemones, then put the mucus on microscope slides and pressed it onto an anemone\u2019s tentacle.<\/p>\n Anemones sting by explosively firing tiny, coiled, venomous harpoons from stinging cells called nematocytes. Using a microscope, the researchers counted and compared how many nematocytes fired between the mucus treatments. They found mucus from clownfish partners \u2013 but not from unacquainted fish \u2013 reduced nematocyte firing.<\/p>\n <\/p>\n To figure out why, the researchers analysed how glycans \u2013 chains of sugars that attach to proteins \u2013 and fats in the mucus changed as the clownfish acclimated to their host. Three weeks into a symbiotic partnership, the mucus\u2019s chemical profile had shifted substantially. In particular, the concentrations of seven different types of glycans had changed. Getting rid of glycans or otherwise tweaking them may be one way to suppress the nematocytes\u2019 firing, says Burke da Silva.<\/p>\n