Mynocks to Mistletoe: It’s Ectosymbiosis!
Tis the season! And not just for the holidays—a new chapter of the Star Wars saga is knocking at our doors.
Tasked with the near-impossible mission to bridge the gap between the Season of Giving and the galaxy far far away, the missing piece to this puzzle turned out to be right under our nose: the mystery of ectosymbiosis, nature’s way of keeping us up-close and buddy-buddy with the animals that live in, on, or under our skin.
To set the tone, let’s jump back to May 1980 with this classic scene from The Empire Strikes Back, an all-time top moment (see Rolling Stone) that takes place inside the gullet of an enormous space slug.
As always in this universe, there’s a lot to unpack here—like why do mynocks chew on power cables? Or how does a giant space slug breathe in the vacuum of space? Thanks as always to Wookieepedia some mysteries are easy to unravel; as an answer to both, the alien species here are both silicon-based lifeforms. A recurring trend when it comes to sci-fi natural history.
The reason this scene is so enjoyable is largely that it plays on the unexpected. When our heroes first land in an eerie space cave, the mynocks are an amazing and thrilling twist, but the reveal about the giant space slug is so unique—so completely out of the blue—that it propels this adventure and the universe (and the biology!) into a whole new engaging direction.
But we need to ask (quickly, I promise) why it’s such a surprise that the mynocks live inside the space slug to begin with. Even for me, this seems so especially unique for movie monsters…but really that shouldn’t be the case. According to an amazing recent article, almost 40% of all animal species are parasites. On top of that, 80% of plants have a symbiotic relationship with fungi. Also 85% of Americans have parasites living somewhere on their skin. And 34% of shelter dogs! Googling how common parasites are winds up taking you down some fascinating spirals.
Point being: animals that live on our skin or inside our bodies are very common. This applies to both the animal kingdom as a whole as well as our own fleshy human bodies—and if the fictional creatures we saw on screen were an actual representation of real-world biology, we should see far far more parasites and symbiotes on the silver screen…but we don’t! And a large explanation for this trend may be that while biologists know how to recognize, appreciate, and talk about symbiosis as something that’s interesting and relevant, not everyone takes that same approach.
Symbiosis is left in the dust far too often, so for the sake of brevity, here are three big things to know about symbiotes and parasites to help crack through this glass ceiling. Let’s get parasites the screen-time they deserve.
And just for clarity, ectosymbiosis in particular refers to animals that live on the skin or in the gut of other host animals — they don’t have to be parasitic or harmful, but come on, that’s a bit more fun anyway.
Firstly, the man of the hour: mistletoe.
In its natural state (pictured above) mistletoe is a debilitating plant parasite found predominantly to the UK, although three other species are native to North America, Australia, and Asia as well. Amazingly, parasitism has evolved independently five separate times in the mistletoe family, making quite a clear case that the plant has a dastardly evil agenda it’s pushing overall.
As a parasite, mistletoe acts slowly but can devastate plots of forest in under a century — a gif here paints the picture well — by tapping into the host tree’s internal transport of food and water. But it’s important to realize that plants like mistletoe have significant ecological benefits as well. In a good quote from Atlas Obscura:
“Parasite has a negative connotation in almost any context… And yet, as you start to learn more and more you find out there are reasons these organisms are out there and they have a place in the community.”
The clearing out of forest patches, especially those that are old or overgrown, is a necessary process to the cycling of nutrients and the ongoing ebb and flow of wildlife. So, thanks mistletoe for saving Christmas, I suppose.
Also apparently the kissing tradition comes from Norse mythology—not relevant to the story here, but fascinating nonetheless.
For our next parasite we head underwater to find possibly the coolest one around: the tongue-eating louse! Ewwwww.
While mistletoe may be a secret parasite that we celebrate blindly every year, this louse is most clearly and obviously a parasite by every definition and nobody will ever doubt it. It comes from our nightmares as the textbook example of why parasites are scary and gross.
Its significance in this article, and in understanding parasites in general, is to appreciate the lengths to which these animals will sometimes go. The tongue louse will burrow through a fish’s gills and chew out its tongue before replacing the body part and slowly sharing on the fish’s meals for the rest of time. And amazingly enough, the louse does not cause lasting damage to the fish host.
We kiss underneath the stealthy plant killer but this nightmare-inducing tongue sucker doesn’t hurt the fish? Parasites: we need to get our priorities in order.
Last but not least, there’s one final ectosymbiotic mess that deserves the spotlight: let’s talk about the human gut.
The human microbiome has been a focus of scientists for many years—the notion that inside our bodies lives a complex, self-contained ecosystem of little bacteria critters that help us stay fit and healthy. Unlike our other two examples, our “gut flora” actually maintain a mutualistic relationship with us, their fleshy hosts. Some researchers have even made strides in classifying these intestinal bacteria as a separate human organ, citing that the benefits to our body are more similar to an organ that a traditional bacterial relationship.
But the fascinating takeaway here is not that the symbiosis is beneficial, but that given how much of our daily wellbeing revolves around a relationship with ectosymbiosis, we think so little about the creatures that live inside us. Research within the past few years has told us that antibiotics reek absolute havoc to our internal microbiomes, and yet the problems persist with little efforts to curb this hazardous trend.
This article isn’t an attempt to preach about bacterial health, but rather to decode our innate understanding and acknowledgement of symbiosis in our lives. From the struggling paradigm shift over our own microbiome, to the lack of awareness around mistletoe’s destructive capability, to the shock and awe at the mynocks in Episode V, we don’t like to devote much brainpower to understanding how symbiotic relationships really work—both in the real world and in fiction.
So the next time you’re shopping in the grocery store for fruits and veggies, think about the fact that some fish in the ocean have a tongue that is not really their tongue, but actually a little bugger.
And let’s all do our part.
