People have been trying to understand how predator and prey can stay balanced for at least 2,400 years. The Greek author Herodotus asked the question in his book.
When Charles Darwin published his theory of evolution in On the Origin of Species, it raised an even more difficult question: why don't predatory animals evolve to eat all their prey and then go extinct themselves?
The process of evolution may not be possible to create prudent predators that can avoid extinguishing their own prey. Evolutionary biologists strongly criticized the idea of prudent predator in 1960.
Under the influence of anti-communist sentiment linked to the cold war between the Soviet Union and the US, biologists argued that group selection was unlikely.
Although modern evolutionary theory has moved beyond the dichotomy between individual and group selection, skepticism about the latter still exists.
In a recent study published in Ecology Letters, my colleagues and I show how this delicate equilibrium between predator and prey could have evolved.
A predator species has evolved to avoid consuming as much and as aggressively as it can. Predators are restraining themselves for the benefit of other members of their species and future generations.
If a predator is moved to a place where they don't belong, they may overexploit the prey around them. The population of the Indo-Pacific lionfish has rapidly expanded in and around the Gulf of Mexico and the eastern Mediterranean Sea.
Smaller fish and shellfish are fed by lionfish. Ecologists were concerned that few other fish species would survive their presence in the Gulf of Mexico. Something else happened instead.
Lionfish populations began to fall in the Gulf of Mexico. Lionfish are not such strong competitors because they overexploit their prey.
Evolutionary pressure to feed less ferociously is what is causing the lionfish populations to dwindle. They are expected to adapt to their new environment by becoming prudent predator.
There is more to be learned from this. In modern, westernized societies, there is an idea that everyone's pursuit of personal benefit will benefit society as a whole.
CEOs of public corporations are expected to act for the benefit of their shareholders alone. Even if a competitor is lost, they will not support them.
The survival of the fittest is an analogy between market economics and evolution.
The survival of the fittest principle is followed by Prudent Predators. The fittest organisms here aren't able to produce the greatest number of surviving offspring. The one that succeeds in generating the most colonies is the one that succeeds.
Colonies of species that overexploit their resources collapse before being able to spread to other places. When societies were not globally connected, similar principles were applied to human choices. The collapse of societies that overexploited their resources would allow more prudent societies to expand.
imprudent actions of people in one place can harm people in other places. Tar sand fields in Canada may be the source of the oil heating my poorly insulated home.
The survival-of-the-fittest mechanism cannot work anymore. The analogy with nature is no longer the same. The belief that the pursuit of individual benefits will lead to balance in society and economics is no longer supported.
Queen Mary University of London has a Reader in Theoretical Ecology.
This article is free to use under a Creative Commons license. The original article is worth a read.
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