Wednesday, 30 March 2016

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.

Wednesday, 23 March 2016

Dabbling in Domestication: Why Can’t I Ride a Polar Bear to Work?

Civilization is a pretty astounding thing. The idea that one species can rise up from the struggle of nature to separate itself into an organized, globally-connected network of distinct but related cultures is pretty impressive; but it is also wrong. The connectedness bit is fair enough, but the idea that humans built civilization without help from any other species just doesn’t stand up to scrutiny. To say nothing of the immensely cooperative plant species we have manipulated to make our way of life possible, there are a handful of animals that have contributed substantially to our comfort and well-being.

Domesticated animals are ingrained in every society in the world to the point where their names and sounds of their names are among the first things that children learn. But the curious thing about these creatures is why there aren’t more of them. Given that animals have proven so useful to people (and vice versa), why, out of the millions of species that exist, are there only eight real cornerstone species of human society? What is so special about cows, sheep, pigs, goats, chickens, horses, cats, and dogs?

In his enormously popular book Guns, Germs and Steel, biologist Jared Diamond lays out six criteria that determine if a species is eligible for domestication. Many animals demonstrate a few of these traits, but all six are required to turn beast into buddy. The rarity of finding all of them in the same animal goes a long way to beginning to solve the mystery of domestication. They are:
  1. Easygoing eating habits – domesticated animals have to be able to live off food they can forage and scavenge in and around human settlements.
  2. Fast growth (relative to humans) – an animal isn’t much use if it takes a decade of care to become big enough to pull a plow.
  3. Willingness to breed in captivity – you can’t be shy if you live and love in a barn.
  4. Docility – cows are a lot calmer by nature than water buffalo.
  5. They don’t panic and flee when startled – or they have a stronger instinct to stay in a herd than run off on their own.
  6. They conform to social hierarchy – they follow a leader like… well, sheep.

As awesome as it would be to have a grizzly bear bounce at your night club, they are severely lacking in trait number 4. A lack of docility also explains why horses have provided transportation for millennia, while the more aggressive zebra is left to graze the savannah in peace. Elephants have been tamed here and there, but have never achieved true domestication because they take 15 years to reach their adult size. These criteria matter.

When humans have identified and latched onto these six characteristics, we have been able to form some amazing partnerships, but as interesting as what we have been able to achieve is, there are the unintended consequences of selectively breeding for desired traits; what evolutionary biologists have dubbed “domestication syndrome.”

As it turns out, when you take a wild animal and domesticate it, there are a set of physical changes that occur that have little to do with any of the six criteria, but seem to go along with them anyway. Domesticated animals – when compared to their wild cousins – general have smaller brains, shorter faces, smaller teeth, weaker muscles, floppy ears, and blotchy coats.

The reason for these changes has long been a mystery, but recent research into the genes responsible for some of them has provided some clues as to why domestication syndrome is a thing. Apparently, selective breeding has tapped into a set of cells called the neural crest which, during the development of a fetus, shapes many of the features that change when animals are domesticated. Interestingly, changes to the genes that control the growth of these cells have also been connected to calmer, friendlier dispositions. There is even a human condition called Williams Syndrome, which manifests as a mild variation in facial development and unusual levels of friendliness. In other words, friendliness and floppy ears are genetically linked.

But perhaps the most interesting thing about the features of domestication syndrome is that a lot of them can also be found in people. We may have big brains but our teeth, muscles, faces, and general physical presence pale in comparison to a below average chimpanzee. As we have domesticated animals, society has domesticated us. Something to remember next time you start to suffer from human superiority syndrome.

Friday, 11 March 2016

Sketchy Fact #115: A Sweaty Situation

You sweat enough each day to fill a 1 liter milk jug. More if you exercise that day.

Wednesday, 9 March 2016

In Defence of Earwax

For something that is located so close to our brains, we spend surprisingly little time thinking about our earwax. That is likely because earwax doesn’t appear to do a great deal for us. Mostly, it is just a nuisance that we have to clean out every once in a while.

That may be the common perception, but earwax is far more useful and interesting than we think. For starters, the type of earwax you produce is directly linked to your genetic ancestry and has implications for your personal hygiene. Yes, as it turns out, there are actually two distinct types of earwax. If your ancestors hail from Africa or Europe and you stick a Q-tip in your ear (something that is never actually advisable as you’re more likely to pierce an eardrum than to get anything clean) you are likely to pull out something yellow and wet. Undertake the same ill-advised ear regimen if you happen to come from a family with links to Northern Asia and your earwax is far more likely to be white, dry, and flakey.

It may seem like a trivial biological quirk, but evolution is a picky business and triviality is rarely tolerated. If it served no functional difference, we would expect the proportions of people with each type of wax to be basically random, but they’re not. Among Europeans and Africans, 97 to 100% have wet earwax and 80 to 95% of North Asians have dry earwax. The numbers are a little more mixed for South Asian, Native American, and Pacific Island Demographics (30 to 50%), but there is definitely some selection going on.

So what is the functional difference? Well, as unpleasant as it may be to hear, wet earwax is sticky and it stinks. The stickiness is thought to help keep insects from crawling into your ear canal if you are unfortunate enough to live somewhere where that is likely. As for the stink, we’re not sure, but it may have something to do with pheromones. Wet, smelly earwax is caused by the same genetic mutation that produces the chemical in sweat that bacteria feed uponto produce body odour, so those of us who are now self-conscious about the smell of our ears might need to stock up on deodorant as well.

Earwax isn’t only interesting because of the stench implications, however. It can also be used as a marker of physical health. Scientists can take a sample of your earwax and determine whether or not you are suffering from certain diseases, long before they could discern the same thing from your blood or urine. Ironically enough, the two diseases earwax is best equipped to diagnose in their early stages are ones named for their eventual effects on urine: Maple Syrup Urine Disease and Alkoptunuria (black urine disease). The former may sound hilarious, and is in fact named for the sweet smell it gives to urine, but that smell comes from enzymes a person’s body would normally use to provide nourishment. Peeing out things you need to live is generally bad news and Maple Syrup Urine Disease can be fatal.

Finally, earwax can be useful in determining details about personal life history. This isn’t something we use it for in humans just yet, but in 2007, when a blue whale died in a collision with a ship near Santa Barbara, California, marine biologists were able to use a plug of its earwax (which happened to be over 25 centimeters – or nearly 10 inches long) to determine the levels of stress hormones in its body and the contaminants in the water it swam through at various points in its life. Whale earwax is laid down in alternating light and dark layers, each representing about six months of time. Human earwax generally doesn’t get to this point, but it may still be useful in determining exposure to toxic chemicals and other harmful agents in forensics.

Try to keep all this in mind next time you carelessly stick a finger in your ear to scoop out some wax. The gunk on your finger holds secrets about your family, medical, and personal history. So, in a very real sense, you are what you pull out of your ears.

Friday, 4 March 2016

Sketchy Fact #114: Empty Planet

Of all the species that have ever lives on Earth, approximately 99.9% are now extinct. As Bill Bryson puts in in A Short History of Nearly Everything, all life that currently exists could be attributed to a rounding error.

Wednesday, 2 March 2016

The Nature of Fear

The thing I hate about horror movies is the silent moment before something jumps out to scare you. The anticipation and the knowledge that there is nothing you can do to prevent yourself from jumping out of your skin is enough to make you want to hit fast-forward (or just skip ahead if you’re too cool to still own a VCR). The reason you can do nothing to avoid the jolt is because millions of years of evolution have shaped your brain to respond this way. It is a reflex that saved the lives of a good portion of your ancestors over the past 4 billion or so years, as they have been forced to flee from lions, bears, and slightly larger bacteria.

But it turns out that fear isn’t only good for individuals; it can benefit entire ecosystems. Recent research into the interactions between large predators and their prey has revealed that the knowledge that something may be lurking in the bushes, waiting to pounce on you, can change the way you behave just enough to have far reaching consequences. We owe this knowledge to a population of lazy, gluttonous, raccoons who live in British Columbia’s Gulf Islands.

The Gulf Islands are something of a northern paradise. They lie in the patch of sea between Vancouver Island and the North American Mainland. Paddle a canoe along the seemingly infinite coastlines of these islands and you’re likely to see everything from bald eagles, to harbor seals, to killer whales, to sea otters. A few things you likely won’t see, however, are bears, wolves, and cougars. That isn’t to say that these animals don’t belong there; they have just been chased away by decades of humans who value a good view and the safety of their pets over robust food chains.

As a result of the lack of land-based predators, the Gulf Islands are also home to raccoons… a lot of raccoons. Some people would say too many raccoons. The thing about raccoons is that they are smart. They quickly catch on when they have nothing to fear and the consequence is that they will spend literally all day scouring the island’s beaches for clams, crabs, and whatever else they can get their grubby little hands on. This is what science calls a trophic cascade. Remove one species and watch how it all goes south.

University of Victoria PhD candidate Justin Suraci noticed the effect this was having on the ecosystems of those beaches and decided to try an experiment. Suraci rigged up a series of speakers along beaches with particularly bad raccoon problems and began blasting the scavengers with sounds of dogs barking. The results were a 66% reduction in the time the raccoons spent foraging. Suraci also tried playing the sounds of sea lions through the speakers and found that the raccoons just ignored them. Clearly it was fear of a specific predator driving the leaner diet plan. The reduction in foraging time observed on the beaches of B.C. is more than enough for ecosystems within which to stage a recover.

But this isn’t the first known evidence of a trophic cascade caused by removing top predators from a region. Yellowstone and Zion National Parks in the United States have reported that rebuilding populations of wolves and cougars within park boundaries would actually reduce soil erosion and alter the course of their rivers.

In Yellowstone, the extinction of local wolves during the 20th century resulted in an explosion in elk numbers. Those elk graze on the vegetation along the park’s riverbanks and eventually eat all of it away. Plants along a river don’t just look nice, though; their roots actually hold the soil in place against the never ending flow of the river. With less vegetation, the rivers eroded their banks faster and generally started flowing more quickly, altering the environment for the fish and amphibians that depend on them. Since wolves were reintroduced, park officials have noted that the pattern has begun to reverse itself. In Zion, the lack of cougars is presently having the same effect on deer populations and local rivers, but cougars are slower to rebound than wolves.

In the end, it seems that if we want to enjoy the beauty of nature, we can’t pick and choose the animals we want to have around. Especially in the case of predators, removing a single species can have dramatic consequences to both, the food chain and the environment itself. The island-living raccoons in B.C. will soon wise-up to the speaker situation and resume their foraging unless their natural predators are reintroduced. God help us if they figure out how to make cups out of coconuts.