Whatever else happens for you today, it might be the day that you find out butterflies drink crocodile tears. You’re welcome.
Today’s Moment of Science… absurdly cute commensalism.
Most of us have a passing familiarity with the concept of symbiotic relationships. There are several types of symbiosis. When we think of the concept what often comes to mind is mutualistic symbiosis. This is when both organisms benefit from their relationship. You and the bacteria living in your gut have a symbiotic relationship; you give it a hospitable environment to live in, it helps you poop regularly, everyone’s happy.
Commensalism is a one-sided form of symbiosis. It’s a relationship between two animals in which one animal benefits and the other doesn’t, but it sustains no perceptible harm either. An animal generally gains housing, nutrients, or transportation from this relationship. It differs from parasitism in that the parasite inflicts a degree of harm on their host.
This type of relationship exists throughout the animal kingdom. The animal boasting the highest penis-to-body ratio, the proud barnacle can find a snug home on the side of a whale. Cattle egrets hang around herds of cattle in order to take an opportunistic snack at the bugs that are kicked up while grazing. And in an utterly effing fabulous display, the emperor shrimp takes up a majestic little chariot ride on a sea cucumber for transportation and protection. Google it, thank me later.
So, butterflies.
In parts of the Amazon rainforest, salt is in short supply. Being scarce and vital to life for so many animals, they show stunning resourcefulness to obtain the mineral. Insects can be attracted to urine or fecal matter because of its salt content. A wide array of animals eat clay licks to sate their sodium requirements, including birds, capybaras, jaguars, and anteaters. Even sloths get off their notoriously lazy tuchuses for some salt from the clay lick.
As for butterflies?
They drink turtle tears.
Why the turtle? You might have heard, the turtle is a slow moving critter. It makes for an easy salt lick for the butterflies. The turtles rarely do much to stop this other than occasionally swat them away. They don’t seem wild about it, but they’re serving an ecological niche and it doesn’t seem to hurt them.
Butterflies get their salt from other sources too. Sometimes, they will make do with crocodile tears.
This has been your daily Moment of Science, suggesting you could be more literal when you joke about drinking the tears of your enemies.
Check out this video from science communicator Phil Torres (@phil_torres on twitter) of the butterflies drinking turtle tears, it’ll make you feel emotions.
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