There’s a buzz in the air these days, a loud one. I’m sure you’ve heard it but it could have easily been mistaken for a malfunctioning drone plane stuck in the trees. The sounds of summer are slowly becoming dominated by the mating songs of male Cicadas, as their relatively long lives culminate in a grand finale. And it sure is noisy.
You may have seen the recent headlines from the media outlets that announced the imminence of a “Cicadapocalypse”, but I can assure you that it will be significantly less dramatic than that. As usual, however, there is some truth behind the warning, only that there may be many more Cicadas around this year than in others, due to the strange periodicity of the Cicada lifecycle.
Cicadas are large-bodied insects, closely related to aphids and plant hoppers, who spend most of their lives as larvae eating roots underground before they pupate to adulthood and crawl up the nearest tree to mate and lay eggs before dying. In Eastern North America there are seven kinds, which are known as Periodical Cicadas, four species of which have 13-year lifecycles and the other three have 17-year cycles.
If you are surprised, either by the length or by the periodicity of these insects’ lifecycles, it would not be an unreasonable reaction, firstly because most insects do not live for much more than a year. Secondly, the odd association with prime numbers is otherwise uncommon among animals, and that is the point. The irregular timing of the mass emergences is the key to its success, as it makes it near impossible for predatory animal populations to track and enjoy the bounty of crunchy and nutritious Cicadas when they become available.
You see, usually predator-prey lifecycles mirror one another to some degree, in that when there is more prey in one year, there can be more predators in the next (more food for them). But as the number of prey decreases, so will the number of predators that can be supported, and so on, leading to a slightly out-of-phase oscillation of predator populations with prey over time. This interaction between the number of predators and the number of prey over time leads to the classic ebb and flow of their populations, as they closely track each other throughout the years.
However, the thing about prime numbers is that they are only divisible by themselves and therefore, prey populations that peak in 13 or 17-year cycles will not overlap with any other peaks in predator cycles, other than during the one rare occurrence of their own mass emergence. This has the effect of preventing a build-up of predator populations in the years prior to the mass emergence and as a consequence, the adult Cicadas find themselves in an environment that is relatively devoid of threats to their survival. As such, many more Cicadas will survive to reproduce than can possibly be consumed. The irregularity of their mass appearances successfully allows the majority of the Cicadas to overwhelm their predators and survive long enough to reproduce.
So if this is all about predator avoidance, what’s with all the noise then? As it happens, the brief duration of adult Cicada lives is occupied by one goal before kicking the bucket, either as predator food or from old age: to attract a mate and to reproduce. It is the male Cicadas who are making the noise and they are doing it to attract and seduce the females into choosing them as a mate based on the quality of his noisy buzz.
The mating call is produced by vibrating two membranes, which are located under the males’ wings and are known as tympanic membranes, resonating at specific frequencies to create the loud buzz. This concept is the same as the one that allows us to make music from a speaker, wherein the speaker’s cone (membrane) is forced to vibrate and the effect is a projection of a loud sound outwards. The Cicadas’ concert may not be music to our ears but it certainly has a charming effect on the females of their species.
Many animals use sound to seduce: crickets and grasshoppers produce a stridulation from scraping ridged combs on their legs or wings, songbirds sing complex melodies, frogs croak and even humans use speech, song and intonation to court and woo one another. In all cases, the underlying principle in the attractiveness relates to the ability of the individual making the sounds.
In nature, courtship behaviours among the animal kingdom typically involve the evaluation of tasks that are not easy to accomplish, therefore a strong performance will tend to imply that it is being made by a strong and healthy individual. These are the qualities that will make the difference between producing average offspring and creating kin that will be inherently more successful at surviving and reproducing in the next generation. Evolution favours those that do better than others and animal reproduction is largely about honing in on those signals that give us hints about the quality of a potential mate’s genes.
Perhaps you don’t think that making a loud and persistent sound really can represent a skill that makes one sexy to others but I dare you to try it. You’ll quickly find that screaming about your sexiness at full volume is really tiring…. I’m sure your neighbours will agree too! The point is easily made though: if you are a big male Cicada, who can make a big and loud noise at the right frequency, all while avoiding the myriad of predators out there, you must have the right stuff for survival and a female Cicada will find that to be irresistible.
So as we sit around the lake, sipping on a cold beverage and try to make the most of our last days of summer, let’s listen to the chorus coming from the trees and acknowledge that the symphony of sound is a remarkable marvel of nature, one marked by a unique time signature and an impressive reed section.
Dr. Adam Oliver Brown
We hear a lot about food these days. Whether it is about healthy choices, food security and feeding the planet, environmental impacts of food production or the science of GMO biotechnologies, hardly a day goes by without food appearing in our headlines.
Curiously, the most readily available source of low-fat animal protein found just about anywhere in the world (outside of Antarctica) is largely ignored by most food cultures. It might be time we start talking about eating insects, or entomophagy.
Putting our icky aversions aside for a moment, there are many good reasons to consider eating insects. Apart from their widespread availability in the wild, they can easily be raised indoors, with a fraction of the footprint (both in terms of land use and carbon emissions) of domestic livestock such as cattle or pork. Also, insect is a lean meat, with up to three times the protein content and with a fraction of the fat, with crickets compared to beef for example. Also, it is a versatile food, which can be eaten raw, cooked or processed, such as being dried and ground into a flour for baking.
Entomophagy is not new or strange to many people around the world, to be sure. One can easily find bulk crickets or woodworms in the markets of Singapore, or termites and grubs in the Ghanaian markets in Accra. Eating insects is also commonplace in cuisines from Brazil, Australia, Japan, China and more. So why is it that entomophagy still carries a taboo in Canadian/American cultures?
The answer may be partly psychological in nature, partly economic and the two are surprisingly linked. Clearly, our western culture carries with it a strongly ingrained entomophobia, or fear of insects, and we don’t tolerate them in our homes, on our lawns, in our crops or even in our thoughts. There is such a widespread phobia of creepy crawlies of any kind that billions of dollars are spent annually on the propaganda of their evil ways and on chemical pesticide solutions to their eradication from every corner of our lives.
This fanatical intolerance of insects was very deliberately fostered and nurtured by post-WWII chemical pesticide companies looking to promote the magical properties of their pesticides (like DDT) and bolstered by an imaginative TV and film media industry that created blockbuster entertainment about killer cockroaches, an attack of the giant ants or tales of mutant wasps that attack human brains via the ear canal. Ouch, scary stuff!
The net effect of this anti-insect campaign has been one in which most of us would rather squish a bug than pop it into our mouths. I am confident, however, that because this is a learned behaviour, it can be unlearned… or better yet, prevented in the first place by reaching out to children and teaching them about the joy and wonders of our critter cousins, before it is stamped out of them by society. Children are naturally curious about all aspects of nature and are particularly intrigued by bugs.
A few weeks ago, I was invited by the teachers at my 3-year old son’s Montessori school to give an insect-related show-and-tell. I managed to borrow several specimen of Stick Insects and Madagascar Cockroaches to bring in for the kids and I was thrilled to see the glee and eagerness from every child who wanted to touch and hold and play with these exotic insects. I kept thinking that the response would have been very different from an adult audience. What a shame it is that this joy of nature is bred out of us as a whole eventually.
Around 15 years ago, back when I was a keen Graduate student in an entomology lab at Laval University in Quebec City, I visited the Insectarium in Montreal for an insect-tasting event. In the foyer of the museum, a dozen chefs were set up behind linen-clothed tables and were preparing gastronomic cuisine of one kind or another, all of which involved insect ingredients. I eagerly ate a multi-course meal consisting in part of ginger-glazed scorpions, garlic-fried crickets, beetle flour cookies and angel-food cake garnished with zesty ants.
At some point during my entomological smorgasbord I noticed that I was being observed by a cautious and curious 8-year old boy, who seemed to take delight in the sight of a grown-up (sort-of) hungrily gobbling down some fried crickets, when I offered him a little taste. The boy reached out his hand to try one when he was noticed by his mother, who was standing just a few feet away.
In the blink of an eye, the poor boy was yanked by the arm, with a shriek from his mother, so brusquely that you could almost hear the socket pop! I mistakenly thought that they were here for an insect-tasting event…. apparently not.
Unfortunately, the boy was so traumatized by his mother’s reaction that it is most likely that his interest in insects was cut short on that very day, one in which a trip to the insectarium could have otherwise promoted a long-term fascination. Too often, our developed entomophobia is inherited directly from our parents, passed down from generation to generation.
We’ve got a long way to go as a society before we are collectively comfortable with all that insects may have to offer us in our lives and maybe even more to consider eating them as regular food.
So whether our conversation about food is related to the challenges of feeding 8 billion+ humans with a smaller ecological footprint or simply to explore the diversity of foodstuffs from the almost 1 million species of insects that exist, we need to start by shifting the flavour of the conversation first, from entomophobia to entomophagy.
Obviously, if we are to have any kind of positive conversation about bugs at all, we need to start with the children and to build pro-actively towards a society that can work with insects and not just against them. Maybe there would be a place for a new “Dickie Dee”-style street vending delivery cart for insect foods…. I can see it now: “Doc Brown’s Bugs ‘n Bites” will be the next food craze coming to a neighbourhood near you. Listen for the chimes as they come around the corner, playing something by The Beatles, of course.
Dr. Adam Oliver Brown
Here is a link to my Facebook page, where you can see some pics and videos of the insect visit with the school children: https://www.facebook.com/DrAdamOliverBrown/