The Butterfly Effect: Grow Weed to Protect Monarchs

If you grew up during the 90's in Southern Canada, Northern Mexico, or anywhere in between, you probably have some fond memories involving Monarch butterflies. While the best that most insects can hope for is humans not noticing them, Monarchs have attained a special place in many people’s hearts mostly because they don’t bite and are strikingly beautiful. The orange, black and white wings of these creatures are so well known that they are probably the default image many of you think of when you hear the word “butterfly.”

Nothing gets to be as popular as Monarchs are, without either a really clever or unbelievably pervasive marketing campaign, and butterflies have opted for the latter. During the 90's, Monarchs were everywhere. I remember days in the schoolyard as a kid when, if the custodian had been particularly neglectful in mowing the lawn, you would have to walk through clouds of fluttering wings to get to the baseball diamond or the sand pit. I used to catch caterpillars and raise them into adults. It was a scene out of a damn fairy tale, but like most fantastic moments in life I didn’t appreciate it until it was over.

It has been a long time since I got to walk through a swarm of Monarchs and that isn’t just because I don’t spend my afternoons attempting to move enough sand to reach China; it’s because the butterflies that defined much of my childhood are disappearing.

It’s not that some evil person or corporation has set out on a mission to wipe out the Monarchs. It actually is the fault of a company many people would argue is evil (Monsanto – another story altogether), but even they aren’t doing it on purpose. See, much of the trouble for Monarchs can be traced back to the fact that they depend on a plant we consider a weed for their survival. They lay their eggs on, spend their caterpillar-hood living on, and exclusively eat Milkweed. Our prejudice for the plant is right in the name.

Milkweed used to be everywhere, mostly because it is incredibly hearty. Give Milkweed half a chance and it will spread like wildfire across farm fields, backyards, playgrounds, railroad tracks, and wherever else there is sunlight and soil. Unfortunately, thanks to genetically modified crops and advances in pesticides, Milkweed has had significantly less than half a chance to grow for the past two decades. On top of this, the forests in Mexico, where Monarchs spend the winters, have been decimated by illegal logging and climate change is making their migration tougher every year.

One of the most incredible things about Monarchs is the distances they travel. It isn’t that a single, massive population constantly exists all across North America; every spring, Monarchs in Mexico take to the sky and fly north. It is this migratory population that exists at different times of the year all over the map. That is part of the challenge; when you rely on so many different places to be environmentally intact, you are very vulnerable to one of them dropping the ball.

In the mid-90s, the total population of Monarchs was estimated at around one billion insects. Since then, thanks to the death of Milkweed and the other factors mentioned above, the population has fallen by over 84%. During the winter of 1996-1997, trees that were literally weighed down by blankets of butterflies covered over 18 hectares of land in Northern Mexico. By 2013-14 the area was less than one hectare. Things are bad in butterfly land.

Fortunately, there is hope. Citizens and environmental groups across the three countries where Monarchs range have taken action. This year, the group Monarch Watch in the US plans to distribute between 200,000 and 300,000 Milkweed plants for people to plant. In Canada, groups like the David Suzuki Foundation are doing the same. Along with these efforts, groups are working with farmers to rent land on which Milkweed can regrow, in what is called an “exchange.” The idea is that farmers rotate spraying pesticides on different areas of their land, setting aside a little each year for Monarch habitat.

Even still, the bugs are in trouble. This past winter saw a pretty impressive recovery in Monarch numbers, before a freak spell of frigid weather in Mexico wiped out as many as 100 million butterflies.

Fortunately, this is a problem you can easily help correct. Go online and find a group near you that is selling Milkweed and get to greening your thumb. If you’ve wanted to get into gardening but don’t think you have the skills, what better way to build confidence than to actively try to grow a weed? With any luck, the butterfly population will grow with your horticultural ego and generations of schoolchildren will be all the better for it.

Sketchy Fact #82: Foot for thought

Butterflies experience taste through their feet. They are like tiny flying Andelites, complete with morphing capabilities.

Metamorphosis: Ch-ch-ch-ch-ch-changes

Elementary school science classes do a great job of engaging young people with the amazing way that things in nature work. They spark enthusiasm for learning and create a passion for science in some kids that eventually leads them to careers of great discovery. The thing about introductory science, however, is that it needs to cover a lot of material in a very short amount of time. The result is that some of the most fascinating topics tend to get glossed over and kids miss out on appreciating how weird and amazing certain things are. This is especially true for the subject of metamorphosis.

 Even the high-level, detail-free version of metamorphosis we get taught in grade school is pretty amazing. An animal begins its life as one thing (the usual example is a caterpillar), enters a period of pseudo-hibernation and emerges as something totally different. As incredible as this seems, you may not have ever stopped and put together the fact that the majority of animals follow this sort of life plan. Nearly all insects look very different at the beginning of their lives than they do at the end, and since insects make up the vast majority of animal species, metamorphosis is more the rule than the exception. Generally speaking, it is weird that you didn’t spend your teenage years in a chrysalis.

The reason that evolution has selected this approach to life for so many animals is amazingly straightforward. If the adult version of an animal inhabits a completely different ecological niche than its offspring, the mature and immature versions of that animal are not competing against each other for food. Caterpillars spend their days munching leaves whereas most butterflies get all their meals through their straw-like proboscis. In the case of the Atlas Moth, the adult version doesn’t even have a mouth. It relies only on fat storage to survive its adult life. It is hard to complete with your children for food when you don’t even eat.

So metamorphosis is a cool, albeit common approach to life on earth, but how does it happen? Most of us are under the impression that after it has munched its last leaf, a caterpillar finds a safe spot and encases itself in a hard shell, inside which it grows wings, antennae, and the other anatomical necessities of adulthood. In fact, what happens it far weirder. The freshly fattened up caterpillar will either attach itself to the underside of a stick, or use silk to create a hammock of sorts to suspend itself. From there, the caterpillar sheds its skin to reveal the chrysalis, which eventually hardens into a shell.

What happens inside that shell is decidedly stranger than you probably think. Rather than simply adding wings onto its usual body plan and calling it a day, the caterpillar effectively digests its own body. Most of the structures get broken down to their constituent proteins and put back together in a totally new form. It is a bit like taking apart your Lego skyscraper to build a car, only the Legos are alive and a lot more gooey. If you cut open a chrysalis, you would basically just find a soup of animal fluids that don’t at all resemble a caterpillar.

Interestingly, at least some of the memories that caterpillars form survive the metamorphosis process. Research at Georgetown University has shown that if you train caterpillars to avoid certain smells, the butterflies they become show the same behaviour. This is because not all the parts of a caterpillar’s body get broken down. The guts and breathing tubes (in addition to the brain, presumably) remain intact and undergo only slight changes.

In the end, whether it is a caterpillar turning into a butterfly or a maggot turning into a fly, metamorphosis is worthy of the label “craze-mazing.” You could almost be jealous if the life expectancy of the average butterfly weren’t less than a year.