The Feeling is Mutual

Coral reef mutualism knocks my socks off

I needed to learn more about coral reef mutualism recently for some client work and it’s just so fun I had to share. Mutualism is a relationship in which both critters benefit. Obligate mutualism means they cannot live without each other- algae and coral, for example.

Maroon clownfish, who are coated in a mucus that protects them from the bubble-tip anemone they depend on, gain safety inside the stinging tentacles to which they are immune, and they offer the anemone their leftovers, or luring other fish close as anemone snacks, in return for their protection.

Facultative mutualism is when species are aided and abetted by each other but not fully dependent. The cleaner shrimp pictured above, which cleans the mouth and teeth of Gymnothrax moringa (the spotted eel), getting a meal in exchange for cleaning service. Or the relationship between coral gobies, which nibble a type of harmful algae, and Acropora (stony) coral.

My personal favorite is the mutualism between boxer crabs and the little stinging anemones they pick up and hold in their front pincers like living boxing gloves. They use the stinging boxing gloves to win at fights and get prey; the anemone benefits because they’re moved around and exposed to much more food to filter feed on than if they were stationery. Brilliant!