Why slimy cheats don't win

Why slimy cheats don’t win
Amoeba fruiting body

Darwin's evolutionary theory predicts survival of the fittest. So why do different survival tactics co-exist, if evolution should always favour the winning strategy?

To answer that question scientists at the Universities of Bath and Manchester have been studying a single-celled amoeba, also known as slime mould, which displays certain behaviours that have been labelled as "cheating" or "cooperating".

In a study, published in the prestigious journal Current Biology, the team found that cheaters don't necessarily win in terms of overall survival, suggesting that biologists should re-evaluate how they define and measure social cooperation.

Their research has medical implications when it comes to developing therapies that use socially successful bacteria to fight diseases such as lung infections.

Professor Chris Thompson from Manchester's Faculty of Life Sciences explains: "If the cheats always win, then according to Darwin, altruism shouldn't exist. To study this we looked at why the single fittest strategy in the amoeba community doesn't dominate."

The team looked at how amoebae compete against each other during cooperative encounters. These strange microbes generally live in the soil as single cells, eating bacteria, but when food is limited, they clump together to form a 'slug' that moves to a different location before transforming into a fruiting body which eventually releases spores to produce the next generation of amoebae.

Development into a fruiting body requires cooperation, with some of the amoebae forming the stalk part of the fruiting body, effectively sacrificing themselves for the benefit of the ones that become spores. Therefore biologists have labelled the individuals that become the stalk as 'altruists', with the individuals that tend to form lots of spores being identified as 'cheats' because they benefit disproportionately.

However, the scientists from Bath and Manchester found that these assumptions don't necessarily tell the whole story. Those labelled as cheats don't end up having higher success than those that appear to lose since the cheats pay a price for their apparent success by producing larger numbers of lower quality spores. These inferior spores have lower survival rates, so overall the number of spores that survive is similar to those amoebae who 'cooperate'.

Professor Jason Wolf, from the University of Bath's Department of Biology & Biochemistry, explains: "Our study shows that whilst there are definitely winners and losers in social cooperation, you can't measure social success just by counting the number of spores these moulds produce. Those that produce lots of spores often make inferior ones that don't have any overall advantage over their competitors.

"Basically we need to look at the bigger picture when measuring social success, rather than making assumptions based on measuring the wrong things."

Professor Chris Thompson adds: "What our study says is that when we look at systems through just one aspect then that system can appear to be unbalanced and shouldn't work, but in reality we are a collection of many features that together determine our success, and so our variety helps to make us more equal."

He adds: "Our study threw up quite a big surprise because the way we measure fitness in a system is currently misleading. By focussing on the number of offspring (in this case ) rather than the quality, we're using an incorrect measurement of success.

"What we thought of as socially successful needs to be re-evaluated."


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Cheating slime mold gets the upper hand

More information: "Fitness trade-offs result in the illusion of social success." Current Biology DOI: dx.doi.org/10.1016/j.cub.2015.02.061
Journal information: Current Biology

Citation: Why slimy cheats don't win (2015, March 31) retrieved 19 June 2019 from https://phys.org/news/2015-03-slimy-dont.html
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Mar 31, 2015
It is survival of the "fit enough". Not survival of the fittest.

Mar 31, 2015
What our study says is that when we look at systems through just one aspect then that system can appear to be unbalanced and shouldn't work, but in reality we are a collection of many features that together determine our success, and so our variety helps to make us more equal.

It also helps that when evaluating 'tame' vs. 'opportunistic' members of a species we're dealing with two dsystems. The tame ones act relative to the environment. For the opportunistic members the other members of the species are part of the environment (i.e. their niche is slightly different). Without the 'tame' members - or other, weaker opportunistic members - around they aren't optimally adjusted to the existing environment (and hence can be outbred by 'tame' individuals elsewhere who are better adapted)

cjn
Mar 31, 2015
FTA:
Professor Chris Thompson from Manchester's Faculty of Life Sciences explains: "If the cheats always win, then according to Darwin, altruism shouldn't exist."


Mis-framing "altruism" is one of my pet peeves when discussing population genetics and evolution. True altruism is an act which has a cost to one individual for the benefit of another, without any motivating factor or compensation. Behaviors that we generally group as altruistic are most often done with a discernible return to the sacrificing individual, whether it be through emotional gratification (conscious or unconscious), social acceptance, self-preservation or advancement, or preservation of genes in the population. I would contend that it is incredibly rare or non-existent because it is a behavior which defies our genetics -which is why selfless actions must be doped by an enjoyable hormone or neurochemical.

Mar 31, 2015
So why do different survival tactics co-exist, if evolution should always favour the winning strategy?

This question is beyond silly. Evolution never said "there can be only one".

Mar 31, 2015
FTA:
Professor Chris Thompson from Manchester's Faculty of Life Sciences explains: "If the cheats always win, then according to Darwin, altruism shouldn't exist."


Mis-framing "altruism" is one of my pet peeves when discussing population genetics and evolution. True altruism is an act which has a cost to one individual for the benefit of another, without any motivating factor or compensation. Behaviors that we generally group as altruistic are most often done with a discernible return to the sacrificing individual, whether it be through emotional gratification (conscious or unconscious), social acceptance, self-preservation or advancement, or preservation of genes in the population. I would contend that it is incredibly rare or non-existent because it is a behavior which defies our genetics -which is why selfless actions must be doped by an enjoyable hormone or neurochemical.


Chemical me this. Why then do selfless actors get the short end of the stick??? TESLA

Mar 31, 2015
"Professor Chris Thompson from Manchester's Faculty of Life Sciences explains: "If the cheats always win, then according to Darwin, altruism shouldn't exist. To study this we looked at why the single fittest strategy in the amoeba community doesn't dominate.""

-With humans altruism only exists among fellow tribal members. Victimizing outsiders is encouraged and rewarded, while within the tribe it is vilified and punished. Each is considered a moral imperative.

The need for cooperation is what created the tribal dynamic - safety in numbers - but it presumes that enemies will always exist to be defended against and overcome.
Chemical me this. Why then do selfless actors get the short end of the stick???
-Because there are always members of other tribes waiting to take advantage of them. Modern society wants us to adopt the concept of a universal tribe but there are many who do not buy into this.

cjn
Apr 01, 2015
Otto:

-With humans altruism only exists among fellow tribal members. Victimizing outsiders is encouraged and rewarded, while within the tribe it is vilified and punished. Each is considered a moral imperative.


That is still not "altruism". The motivating factor is that one's sacrifice for the tribe benefits his family within the tribe or enhances their/their family's survival as remaining members of the tribe. For humans there is always a motivating factor to any behavior, there is either the rational calculus of survival, the conscious or unconscious desire for a chemical stimuli, or a social benefit.

Apr 01, 2015
That is still not "altruism". The motivating factor is that one's sacrifice for the tribe benefits his family within the tribe etc
So what is the point youre trying to make? Are you saying that true altruism exists without the anticipation of reward? Did you hear this in church? Lets see...

"Altruism
the belief in or practice of disinterested and selfless concern for the well-being of others.
"some may choose to work with vulnerable elderly people out of altruism"
ZOOLOGY
behavior of an animal that benefits another at its own expense."

-Well then I guess youre right. And so I would have to say then that 'altruism' doesnt exist. Intratribal altruism was selected for as a way of strengthening tribal cohesion. Tribes whose members did not trust each other would tend to be usurped by those that did.

So it became innate. This doesnt mean that it is natural. Domestication involves producing many unnatural behaviors which aid in survival in the social context

cjn
Apr 02, 2015
@otto:

I'll go ahead and quote myself from my first post: "I would contend that [altruism] is incredibly rare or non-existent because it is a behavior which defies our genetics."

Definition:
altruism in Science
altruism
(āl'tr -ĭz'əm)
Instinctive cooperative behavior that is detrimental or without reproductive benefit to the individual but that contributes to the survival of the group to which the individual belongs.

cjn
Apr 02, 2015
Continued:

Altruism is detrimental to the individual and beneficial to others. In asocial animals, sacrifice by the individual is usually dependent upon the genetic relation of the recipient -thus it serves the individuals selfish genes. In social animals, sacrifice for a group serves to preserves one's place in a group (for security and status), to support the survival of related members, or because there is some physical or physiological reward -again, in an effort to preserve one's selfish genes. In humans, sacrifice for unrelated members of a population is done for status or attention (increasing one's perceived fitness and thus reproductive success), self-preservation (if one thinks that doing so will satiate the needs of the wanting to not be predated), or because one gets a physiological neurochemical reward.

Thus, the vast preponderance of claimed "altruism" actually results in a direct benefit to the sacrificing individual (or its genes).

Apr 02, 2015
Dawkins denied any genetic basis for group selection. But I wonder if he considered the possibility that a healthy and well-adapted gene pool from which individuals could select the best mates, was a genetic preference.

At any rate, traits that are selected for over the course of many gens, whether that selection process is 'natural' or not, becomes genetically coded. We bear gregarious children who seem predisposed to group affinities at the possible expense of repro rights. They seem predisposed to embracing the psychoses of religion and nationalism, both institutionalized and formalized abstractions of the tribal dynamic, because their ancestors were selected for it. Domesticated for such irrational behavior.

This is why superheroes and sports personalities and boy bands are so popular.

cjn
Apr 02, 2015
Otto:
They seem predisposed to embracing the psychoses of religion and nationalism, both institutionalized and formalized abstractions of the tribal dynamic, because their ancestors were selected for it. Domesticated for such irrational behavior.

This is why superheroes and sports personalities and boy bands are so popular.


My guess would be that tribalism, nationalism, or any other external centralizing of the locus of our identities enables for our "greater self" to have more powerand influence (perceived or otherwise) than our "individual self" or "otherized self" (outsider). The power of the "greater self" translates to a perception of greater fitness in social animals; greater fitness implying greater reproductive success. (cont)

cjn
Apr 02, 2015
Further, I'd guess that this is all subconscious and controlled by the appropriate neurochemical stimuli, and because we are sentient but still animals, this stimuli is activated even when an individuals association with an external group doesn't translate into increased reproductive success.

As for superheros and sports stars, they are considered the "manliest of men" (even if its is not a conscious thought), and thus the fittest of men... and the money doesn't hurt.

It is because we are sentient that we can rationalize our conscious decisions, but it is because we are still animals that our unconscious ones present such idiosyncrasies.

cjn
Apr 02, 2015
On altruism, our sentience gives us the potential advantage of being able to make rational, voluntary decisions to render aid or to sacrifice for others independent of our genetic predispositions. Unfortunately, those drivers have evolved to dope our brains into "mis-rationalizing" to ensure that socially beneficial behaviors will occur -and rewarding us for it that, even if we wanted to, we cannot commit an act of altruism in isolation from the self-gratification that it provides.

Apr 03, 2015
"There can be no doubt that a tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to give aid to each other and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection" (Darwin, 1871)
http://rechten.el...RID2.pdf

-Tribalism is enjoying a resurgence in popularity because it explains a great deal of human behavior. We are not animals; we are domesticated animals.

You can make up your own theories or you can research those that already exist.

Apr 03, 2015
"Rude tribes and... civilized societies... have had continually to carry on an external self-defence and internal co-operation – external antagonism and internal friendship. Hence their members have acquired two different sets of sentiments and ideas, adjusted to these two kinds of activity... A life of constant external enmity generates a code in which aggression, conquest and revenge, are inculcated, while peaceful occupations are reprobated. Conversely a life of settled internal amity generates a code inculcating the virtues conducing to a harmonious co-operation..." (Spencer, 1892)

-The reason why tribalism has been resisted for so long is that it tells us that behaviors such as gang membership, bullying, bigotry, and cronyism to name just a few, are normal within the context of the tribal dynamic.

Modern society is intent on preventing these behaviors as it seeks to establish the perception that we are all members of one universal tribe.

Apr 03, 2015
"Darwin's evolutionary theory predicts survival of the fittest."

This is not true at all.

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