The Quantum Mechanics In Migrating Monarch Butterflies

Monarch butterfly migration using quantum biology and magnetoreception to find direction
Photo by Sarah Brown / Unsplash

Given that this is my first post, let me tell you a little bit about myself.

My name is Andres (nice to meet you!) and I'm an undergraduate university student currently situated in the UK. I am also an enthusiastic savant of the curious workings of Mother Nature. This I mean rather holistically; though I am usually more aware of mainstream science, even the little particles surfing around in a yeast cell and the subtle linguistics between tamarin apes will fascinate me.

One minute you may find me skimming books on thermodynamics and enzyme-controlled reactions, while the next I might become enthralled by the endless complexity of pandas eating bamboo sticks. Either way, I'll at least be interested.

'What the hell do I do with this knowledge?' I asked myself one day. And, well, this is the answer I came up with: create a blog.

This blog will mostly include my day-to-day findings on random scientific articles and books I encounter, and most of THAT will probably regard themes in the wacky world of biochemistry. The odd post will feature physics or pure chemistry - and perhaps even maths?? I'll see. There is the caveat that I cannot promise expert-level material here (still in uni!), but I do promise solid chunks of research on my part, as well as the best interpretations that a pretty-damn-good-bachelor can offer. I will also talk about pandas, 'cause I like them.

Other stuff I might include is my experience in a UK university and the joys and peculiarities associated with it, plus any bits of interest I find floating about the web. This of course means that, if my blog somehow achieves enough interest to accrue a few relevant questions from readers, I will do my best to answer them - scientifically.

Finally, while it is my wish that this blog ends up useful to a couple people curious about the world, please note that I will not be using the most rigourous and sophisticated terminology here - not all the time, at least - and I will always recommend you to do your own research when you are interested about any particular matter. It's all about avoiding biases and coming to terms with your own conclusions, after all.

Continuing on; here's a small preview about the kind of stuff I want to talk about.

The Monarch Migration

A few months ago I came across a few butterfly affairs that I thought were rather wonderful, so let me tell you about them.

First, here's a fact: monarch butterflies (Danaus plexippus), a North American species renown for the marvellous orange-and-black stripes on its wings, are migrant creatures that fly from Toronto, Canada, all the way to the mountainous regions of central Mexico during the Winter months. They do the trip back at the start of Summer. This, of course, is to ward off the cold and heat respectively, but the one-way course is roughly 2500-3000 miles, and just that gets a big 'wow!' from me. I mean, I can barely run five miles without exhausting myself to death.

In season, you may find thousands, millions of butterflies all crowding for space in the idyllic forests of oyamel fir trees to the west of Mexico City, with tourists from all over the world (or illegal deforesters, unfortunately) coming to see one of the most beautiful sights on Earth. The monarch butterfly reserve, they call it. Personally, I have yet to witness it, but images on the internet have made me rather envious of those who have. It looks amazing.

Mountain view from Mexico and fir trees
Photo by Catalin Paterau / Unsplash

All this becomes endlessly more impressive when you understand that these little critters are so incredibly determined to reach their haven that, tragically, they actually perish in their endeavour. It's a long way and, combined with a monarch's short lifespan of around five weeks, it simply becomes a slice too much for the original colony to handle. Instead, it is the colony's offspring that make it.

This raises a question: how do the new monarchs know where to fly in order to reach the oyamel fir trees beside Mexico City? For that matter, how do they know the flight back to Canada? (This particular animal migration, being one of the most massive and widespread on Earth, has been studied fervently enough that scientists have been able to show that the path stays constant year after year, with very little deviation in their destinations.)

Scientists have a multitude of hypotheses to this - such as the use of the constellation patterns in the sky and the earth's gravitational strength to be all cool like that - but I will be talking about a different kind of theory for the monarchs' navigation. According to a group of researchers at the University of Massachusetts, it has to do with their circadian clock, i.e. how different colours throughout the day help them determine what time it is. This process occurs mainly when blue light particles (photons) hit a certain protein (cytochrome C) in their antennae, thereby bumping up a pair of electrons in the protein. When these electrons proverbially fall back from their bumped-up positions, the way they fall causes some particular signal to be emitted to the butterfly's brain (called the subeosophageal ganglion, apparently) that tells them what time it is - and, furthermore, where they are on the planet.

Monarch butterfly sitting on a flower
Photo by Justin DoCanto / Unsplash

Without getting too manic about the details here, the latter part of that process (when the electrons are about to fall down) is influenced by the magnetic field generated by the big rock under our feet. This geomagnetic field - which I explore in more depth in my other article - is strong enough to make one of the electrons fall in its own special little way to emit its own special little signal, and their inclination to the surface of the earth affects this.

Biologists have a term for this - they call it an inclination compass. Now, imagine the earth as a basketball, its black stripes moving as parallel to each other at each point on the surface as possible. The result is a greater concentration of black at the two points where all the lines meet, with the longitudinal line halfway on the ball (a.k.a. the equator) sporting the smallest concentration. The strength of a magnetic field (known as its flux density) behaves in the same way; the closer to the equator you are, the weaker the magnetic field, with the poles having the highest magnetic field strengths. This means the butterflies know how far from the equator and how close to a pole they are, but cannot distinguish between poles - which geographically aligns with the monarchs' flight route, as Canadian monarchs almost never travel into the southern hemisphere. Etcetera etcetera.

Some curious molecular biology researchers further argue that there is some quantum wackiness with the aforementioned cytochrome electrons being entangled going on here, but that gets a bit too complicated for what I wanna get at. If you're interested, however, do take a look at his book, Life on the Edge - though controversial, the theories described in it are astounding.

Anyway. This entire process is known as magnetoreception. Many animals have been shown to pack this in their sensory materiel - from European robins flying to Africa in November and sea turtles swimming their way across the Atlantic, to fruit flies being paragons of evolution - but for whatever reason we humans fall short in this. While we have all the necessary equipment (cytochrome protein in eyes, electrons, brain, etc.), it would appear that, one day, evolution simply decided to cut off our brain's ability to comprehend however magnetic fields affect us, and so we do not have a built-in GPS like butterflies. That said, however, a number of researchers have repeatedly argue over this concept. Some have experimented by wrapping blindfolds over a group of (willing) test subjects and see if they could consistently point towards the same directions, and some other research institutes have negated the evidence with fervid doubt and their own experimental results. It is rather difficult to avoid bias and placebos in that type of experiment, after all. All in all, there is not enough evidence to reliably state that humans can sense magnetic fields, and so the common consensus is that we simply can't. Oh well.

Looking beyond our inability to detect the North Pole instinctually, I think we can agree that the Monarch Migration is beautiful - but also that the going-ins of life, even inside the minutest of its kind, can be equally as beautiful. As a biochemist, I hold witness to this most days of my everyday life, and I hope this article was able to convince you of it, too.

If not, maybe the next post will do it.