Shortly after first moving into this area, there was a large cicada invasion and first learned about the 17 year cicada. We had cicadas where I grew up, but I assumed they were annual events. If there was a specific outburst for the 17 year variety, and of brood X in particular, it probably occurred when I was younger and not paying much attention. Maybe I did notice, but it did not make a lasting impression. I was very impressed by the event that occurred when I first arrived here.
I may have noticed them more because I did a lot of walking at the time. Because I would walk everywhere and so often I would notice the inconvenience of having to watch where I was stepping and the annoyances of the fluttering past my field of view. Even the shadows they cast while fluttering overhead are distracting. Later, their presence would show up in dead or dying young branches in trees. By late summer, I compared the appearance of trees as being decorated like a Christmas trees but where the ornaments are dead branches. The distribution of the dead branches was similar to a decoration.
I had just moved to the area and at that time I assumed I would be here only temporarily. I recall thinking if I would be here the next time they arrived. I was. At that time I had a house with a yard that had a lot of trees. I got to watch them more carefully. Then I wondered if I would be around the next time, and here I am.
Although I am fascinated by the phenomena, it is not an obsession. I lost track of when they happened and when they will happen again. Now I do recall making a calculation that it would be 2021, but I had to be reminded by some news article or other mention.
Curious about it, I decided to do a search and I found lots of articles exclaiming that this is the year. The surprising thing about most of these articles is that they spend a good fraction of the article explaining that they are safe to eat, and even suggesting ways to make it a good meal choice. I vaguely recall a similar discussion the last time.
Turning cicadas into a food crop does not work because they are not annual. If this were an annual occurrence, we would develop some method to harvest them, process them, and distribute them. We would have an annual festival featuring cicada dishes, or we would find ways to turn to into protein additives to snacks. We cannot do any of those things because they appear once each 17 years, coincidentally about the number of years to mature a human.
From the first time I really noticed them, I noticed how docile they were. They do not attempt to flee if you approach. They will even land on you and not be on any hurry to leave. If you pick them up, they react as if they like it. Their bodies and behaviors have virtually no defenses against predation. They seem to specifically seek to be eaten. It is like when you pick one up, they are saying “go ahead, eat me, you know you want to”. Their bodies are substantial enough to look like a good meal, especially for smaller animals and birds.
We had a stretch of cool weather earlier so their emergence this year was delayed a bit. They just started emerging a few days ago. The early emergence is very noticeable by the carnage. First thing you will notice are these disconnected wings flying around. Then there are piles of partially eaten cicadas at points they aggregate at.
For the wildlife of birds and mammals, the first appearance of the cicadas, especially immediately after they begin emerging from the ground, must be a like a bountiful feast. They are all excited about having such an easy meal, and for many the meal coincides with their own offspring needing food.
The tremendous bounty of the early arrivals is followed by an even bigger population, and that then is followed by an even bigger population. The predators are overwhelmed. Even though the cicadas remain nutritious and the animals may be hungry, the predators show signs of being tired of eating cicadas. They will soon just ignore them.
I noticed this yesterday during my walk. I noticed a crow land on the sidewalk about a half block away. It was approaching some dark spot on the ground and had its beak close to nearly touching it. The crow flew off without snatching anything as if what it saw turned out to be a rock. I walked to the spot and noticed it was a cicada that was not dead. The crow wasn’t interested in eating another cicada.
I see this with other birds as well. At first, they make sport of knocking the cicada out of mid-flight and then subduing it on the ground. Later the same species will just ignore. They have had enough.
I imagine that this abundance makes raising the predator’s job easier in feeding their young. There will be more surviving young this year and they will be expecting a similar bounty next year or whenever it is their turn to reproduce. In evolution terms, there was a signal that there is bounty of food that will appear in great enough numbers to support a much larger predator population. That successor population would be disappointed, and so will many generations afterwards. By the time the next wave emerges there would be no memory of the last time, this would appear to be a new normal all over again.
I get the impression that cicadas are deliberately messing with evolution itself. These are creatures that make themselves too easy to eat, and they arrange to do it in such numbers that anyone who wants a meal can have one with virtually no effort. This is described as a survival strategy by the cicadas, survival by overwhelming the predator’s appetites. I think it might be more than a survival strategy.
Their life cycle messes up the normally expected harvests for the predatory species. They have more food than they know what to do with, and this food is practically begging to be eaten but with their large size and their lack of defense or even evasion. This leads to a larger than expected survival rate of the next generation who expect a similar bounty when it is their time. It is like there is a larger plan in play. The designers of the 17 year cicadas are aware of the annual game the other species are following. They are hacking the system everything else is following.
There is a lot of counter-evolution aspects to these cicadas. The sheer numbers indicate that they could easily kill their hosts long before they 17 years are up. Instead, they are content to wait those 17 years just extracting enough to stay alive. I have no idea what their underground life is like, but I imagine it to be like a person in a persistent vegetative state, hooked up to a life support system that provides just enough to keep the body alive. To do any more would kill their host tree. There are just too many of them.
I don’t understand how evolution would lead them to conclude on a very consistent waiting period of such a large number of years, and that number being a prime number. There appears to be something very deliberate in that choice. I can’t imagine evolution stumbling on this number by trial and error, but I’ll concede it could have gotten lucky. The amazing thing is that it would choose any number of years greater than one. This planet has seasons, and each early summer season is just right for the cicadas to do what they do every 17 years.
They could emerge every year and have an annual lifecycle. I realize that this would give the predators to opportunity to adapt so that most cicadas would get eaten, but as with other predator and prey relationships, there would be some prey that manage to complete their cycle. There would be some equilibrium. Instead they strive to wait a very large number of years.
For something like a cicada, if it is able to last 17 years doing its thing underground, it should be able to do it forever. Perhaps the life cycle of trees provides the motivation. When they are swarming, they are checking out the trees, and they appears to target very specific trees. Two trees of the same species may be near each other but only would would get all of the Cicada’s attention. They are shopping among the latest real-estate choices.
Remaining mysteries are how they count the years so well to be so synchronized over such a large geographic area and why this one particular 17 year period is so popular. It should be possible for there to be 17 different broods each having its own year for the territory they are in. Over the many generations there should be drift. There is something that is drawing them to stay on this particular schedule.
Cicadas show evidence of a super-evolution. Super evolution is like super-natural but applied to evolution in particular. They should not have evolved given the circumstances on this planet. At least we do not know of any external circumstance that would favor a 17 year cycle and favor this particular cycle. There may be some 17 year phenomena we have yet to discover. Alternatively, this is evolutionary adaptation to something that is supernatural.
I go back to the food source conundrum. The abundance of cicadas make them a candidate for harvesting for human food. I have no doubt we would come up with some way to work them into our diet. To do this, we would need an economy built on harvesting, processing, and distributing them. There is no practical way to build this kind of thing for an event that occurs once per generation.
This coincidence of the 17 year cycle is very intriguing. While humans reproduce all the time, it does take about 17 years to get to reproductive age. During that time, the child will experience a brood X cicada just one time.
Personally, I have never eaten a cicada. I read that they have a taste that is similar to asparagus. That does not surprise me because both come out of the ground immediately in their harvestable form, and asparagus is similarly alien with its own super-evolution qualities. I like eating asparagus. I grew it when I was a child but even then I planted it apart from the rest of the garden. I recall a sense that it did not belong near the regular vegetable garden. It was a very strange plant. I liked its strangeness.
There is no direct relationship between asparagus and cicadas except both happen to emerge out of the ground ready to eat, and both present their earlier emerges as something very enticing to eat: plump and tender. Supposedly they taste similarly. I imagine the cooked texture would be similar too. Both appear to offer no resistance to being eaten. They may even be disappointed in not being eaten because that means they have to go through the burden of reproducing. For the cicadas, the whole reproduction process takes a lot of effort and struggle.
In human terms we see the reproductive act as a delightful event that is worth the effort to reach that point. I think we assume that this is a constant in nature. There is a drive to reproduce and underlying that drive is the prospect of a pleasurable reward of some form. We assume this is necessary to assure the production of the next generation. I don’t think this is necessarily true. Reproduction may be a chore and one that ends badly for the parent. They may want to escape this obligation. The cicadas might be in this category. When caught, they do not appear too concerned about missing out on their mating prospects.
I think they are messing with evolution or hacking it. Or more precisely something creating them to do this. They deliberately wait 17 years to avoid predation. During that 17 years, they draw so little from their hosts that nothing notices. They are mostly just waiting. Then they come out and overwhelm everything. There is something deliberate in this cycle. There appears to be an intent to tease or harass the evolution of all the other species, up to and including humans.
Their creator probably does want us to find a way to harvest them on an industrial scale but on the 17 year cycle where the year varies depending on the territories. We can do this by creating a kind of a ceremony and feast that occurs once every 17 years. To make this happen we would need an investment of some kind of infrastructure that like the cicada would lie dormant for 17 years.
There may be a ecological benefit for humans to find a way to do this. It is only human activity that can stop this behavior, or at least keep it from getting so overwhelming to everything else. If we could harvest these in great numbers, there would be less strain later by a predator over-population or damage to trees. The entire behavior is begging humanity to do something about it.
This behavior defies our scientific understandings of biology, life, and evolution. There should not be a creature that presents itself as such an enticing meal and yet offer no defense against predation. In this particular case, evolution appears to favor the production of food. This is not how evolution is supposed to work. I recognize it is a possible survival strategy, but these creatures have lots of other and easier strategies. It might be a fortunate mistake that happens to work for the species.
The 17 year cicada’s and the brood X existence might instead be a deliberate choice to send a message to all the other species that it understands evolution. The choice of 17 years appears to be make this message relevant to humans in particular. That message may be telling us that our understanding of evolution is wrong. In some way, species are aware of the evolutionary pressures of other species. They can act on this awareness to mess things up for them, but in a playful harassing way. This creature knows how to create a bountiful feast on a schedule that does no good to any other species.