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Predators May Have Evolved To Avoid Overexploiting Resources

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Mar 11, 2022

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Image Credit: Getty

Natural evolution may have a message for us, and it’s an instructive one for our future. A new study shows how predators may have evolved to consume prey to an extent that’s just sufficient — to ensure they don’t threaten the survival of their prey’s populations. In other words, they’ve mastered the — dare we call it — “art of optimal consumption.” It’s a book that our economic theories could take a leaf or two (or several) out of.

Published in Ecology Letters, the study suggests that “in complex model food webs, prudent predation evolves as a result of consumer-mediated (‘apparent’) competitive exclusion of resources, which disadvantages aggressive consumers.” This is called the “prudent predation” theory — and it was a controversial one for how it suggested that evolution takes place in groups rather than as individuals.

The controversy goes back to theories of evolution in the 70s which, under the purported influence of anti-communist sentiments in the Cold War, insisted that evolution had to be an individualistic process.

It may not be surprising to learn that evolution favored prudence — or the ability to limit consumption for the benefit of the species’ survival. The authors point to a “delicate equilibrium” between predator and prey as a result of evolution, where predators unknowingly ensure the survival of their species through restraint in their consumption and aggression. In other words, they don’t over-consume, just because they can.

Moving species from their natural habitats to new locations, moreover, can increase the tendency of overexploitation and lead to the eventual collapse of the population. The study looked at how different species populations changed over time, with one example being that of Signal crayfish in Swedish lakes. With no other convincing explanation behind their population collapse, overexploitation of resources was speculated to be one strong possibility. This was also observed with Argentine ants in New Zealand and Lionfish in the Gulf of Mexico.


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Australian Cane Toads Are Evolving to Be Cannibals Due to Overpopulation


“In modern, westernized societies, there’s a deep-seated idea that everybody’s pursuit of personal benefit will ultimately benefit society as a whole,” writes study author Axel G. Rossberg in The Conversation. The idea of prudent predation, however, gives new meaning to the oft-misconstrued “survival of the fittest” adage. Where it is typically taken to mean that individuals that can reproduce the most are evolutionarily favored; prudent predation redefines it in terms of the ability to generate the greatest number of new colonies. Overexploiting resources in one place can lead to a species dying out — not very fit for survival, in other words.

It’s an evolving theory in itself, but one that is gaining strength with time. “Population control is a stark example of strong conflicting interests, setting the individual against the group. It is not surprising that this issue has played a key role in a historical debate concerning the viability of group selection as an evolutionary force,” write researchers in another study on the subject. “If individual reproductive potential is not maximized, a great part of the body of evolutionary theory will have to be reconsidered,” they further add. The idea is that keeping individual reproduction from rising so much as to threaten “demographic stability” is key to ensuring species survival. Tempering individual self-interest, in other words, may ensure the security of future generations. The theory, moreover, could answer our climate woes — for which individual overconsumption is one key factor to blame — if we learn in time.

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Written By Rohitha Naraharisetty

Rohitha Naraharisetty is an Associate Editor at The Swaddle. Previously, she was a freelance writer and independent researcher working in the intersection of gender, social movements, and international relations. She can be found on Instagram at @rohitha_97 or on Twitter at @romimacaronii.

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