Evolutionary Arms Races
It’s one of the standard topics in an ecology class, or an evolution class, or really, these days, even general biology. It’s an idea there on your favorite natural history program on TV, the idea that over the course of evolutionary history, predators and prey (which includes herbivores and plants) have developed characteristics to help them eat and/or not be eaten.
I recall the first time I saw something online that was expressing incredible shock at the idea that plants knew when they were being eaten, and I thought, well of course they do, how else would they know they need to produce those inducible defense mechanisms? Some plants only produce their defense mechanisms when an herbivore is present, and feeding, and to do that, they must sense that they are being eaten.
It’s not exactly the same type of sensation that we have, but then we often use human analogies to try and understand the way non-human species function, and really, it’s not unreasonable to do so. Comparative anatomy and physiology, particularly within the framework of physical adaptations to diverse environments, is foundational to understanding evolutionary biology.
Arms race is very much a human way of thinking, but again, it is useful.
What occurred to me the other day is that inserting a bacterial gene into a plant so that it can kill its potential herbivores, which we do with plants genetically modified to produce the Bacillus thuringiensis (Bt) toxin, disrupts that evolutionary arms race in ways unpredictable.
Giving corn and cotton the ability to kill caterpillars (and ergo butterflies), beetles and various other flying insects, nematodes, etc. is about like supplying the latest and greatest in military technology to one group, let’s say the Rohingya in Myanmar, and with it they can wipe out the Buddhists who are trying to wipe them out, and then all the rest of the Buddhists in the world, too, just because they can.
They’re armed for it.
The problem with that analogy, of course, is that I’m talking about the same species, humans, and we can wipe each other out all day and it won’t impact the earth’s ecosystems in a terribly bad way, at all, unless we kill lots of other stuff along with us. If, on the other hand, those Bt toxin producing plants are killing caterpillars, and beetles, and various flies and nematodes, so many target species, and non-target species, too, it might very well throw entire ecosystems into a cascade of local species extinctions, starting with the vertebrate species that feed on those target species.
Perhaps I'm being an optimist, but I think that the Rohingya likely would not kill all Buddhists, they are, after all, human beings, and they can make the choice not to. The corn and cotton armed with Bt toxin cannot decide they’ll spare their herbivores, they’re going to kill the vast majority of them, because they can.
Those they don’t kill will be those which are resistant to the toxin. New super pests, not directly genetically engineered by humans, but just as surely the result of our interference with nature as are antibiotic resistant bacteria, another lesson we’ve not yet learned.
So let’s plant Bt corn and Bt cotton (snark), thousands and thousand of hectares of them, let’s arm those poor plants against those pesky herbivorous insects, wipe them all out. Let’s wipe us all out.
That’s what arms races are most useful for.