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Stinging insects that die after using their sting once

mslxl

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How was that trait picked out by natural selection?

Thank you.

mslxl
 
I could be wrong, but I believe the ones that die are not actually the ones that would be passing on genetic material anyway. You could almost answer this question by asking why sexless drones have evolved in an insect colony.

As a thought, "energy" devoted to making stinging survivable for the stinger might make the sting itself weaker. The reason they usually die is that they've literally put everything they have into that sting to make it more effective. This sort of specialization (where most of the animals are not actually breeding) means that it doesn't really matter if they live or die, only that they must fulfill their role in the colony.
 
mslxl said:
How was that trait picked out by natural selection?

Thank you.

mslxl
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The genes in individuals that die stinging are shared with other individuals that benefit from the lessons learned by the stung predator.

Recall that stinging insects have bold markings. This is to train their predators that they are not safe to attack.

Colony insects may be thought of not as individuals, but as a single organism, since most members are not reproductive. Worker bees have every justification to sacrifice their lives for the hive since they do not reproduce, themselves, but will give their lives in defense of the colony (specifically, the queen and male drones). Their genes for stinging, dying while stinging, and being painful memories in their predators, are in the queens they are defending.

Think of individual bees as comparable to individual cells in humans. We will, if necessary, punch hard an enemy, and kill a few cells in our knuckles as a side effect, to defend our reproductive survival. The OP question would be like asking, "How is the trait of cell death picked out for natural selection?" It benefits the organism, or the hive which works like a single organism.

For non-colony stinging insects, it works similarly. Think of it as survival of the gene, not survival of the individual -- a modern refinement of Darwinism.
 
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Mr. Scott said:
Think of it as survival of the gene, not survival of the individual -- a modern refinement of Darwinism.
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very good post!. The sentence I quote is, IMHO, crucial. Ultimately, evolution is not about individuals, not even species. It is about the survival of the fittest genes.

Hans
 
Evolution is driven towards survival of the species, not the individual. So it is not just social insects (which can behave like a single organism and which have non fertile workers) which can benefit from this strategem, but other animals too.
Think of the meerkats which take turns acting as lookout for their colonies - the lookout has a higher chance of falling prey to a hawk/other predator, but their behaviour and sometime sacrifice benefits the other individuals in the group, and genetic information which favours this type of behaviour will be preferentially naturally-selected.
 
Deetee said:
Think of the meerkats which take turns acting as lookout for their colonies - the lookout has a higher chance of falling prey to a hawk/other predator, but their behaviour and sometime sacrifice benefits the other individuals in the group, and genetic information which favours this type of behaviour will be preferentially naturally-selected.
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hmm, i'm not sure dawkins would agree with you.....

maybe the lookouts are only concerned with their own relatives' survival......
edit.
that is to say, that this might be their motivation - and any group benefit may just be a consequence......
 
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MRC_Hans said:
very good post!. The sentence I quote is, IMHO, crucial. Ultimately, evolution is not about individuals, not even species. It is about the survival of the fittest genes.
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An interesting perspective on this, from Dawkins:

"Our genes made us. We animals exist for their preservation and are nothing more than their throwaway survival machines." [emphasis mine]

It's hard to think that our bodies, and our very existence while we're at it, may have as its sole purpose the propagation of our genes. But the case for it is compelling.
 
I believe Harlequin's "sexless drone" comment is probably the most important for explaining this type of behavior-- if I recall correctly, bee colonies, like other social insects like ants and termites, resemble single organisms more than most social groups do, in that all individuals are closely related by virtue of being offspring of a single queen. The individual workers who do the stinging and dying are dead ends in the gene stream anyway, so the genes benefit by sacrificing them as pawns for the sake of protecting the queen.

mslxl, have you read Dawkins's The Selfish Gene? It does an excellent job of explaining how a lot of these apparently anomalous behavior traits make sense when viewed from the gene's perspective. I'd highly recommend it.
 
JamesDillon said:
mslxl, have you read Dawkins's The Selfish Gene? It does an excellent job of explaining how a lot of these apparently anomalous behavior traits make sense when viewed from the gene's perspective. I'd highly recommend it.
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like how in some ant colonies, sisters can be genetically 2/3 the same, making siblings not offspring care the optimum selfish gene policy*

*actually they might be sterile, but nonetheless it shows how society stratifies across rather than down.....
 
andyandy said:
like how in some ant colonies, sisters can be genetically 2/3 the same, making siblings not offspring care the optimum selfish gene policy*

*actually they might be sterile, but nonetheless it shows how society stratifies across rather than down.....
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Nuts, I was about to say that.

Although interestingly blind mole rats are the only known mammals to have a hive society with only one female breeder, and they are all normal diploid with none of this messing about with different numbers of chormosomes that insects seem to enjoy so much.
 
Deetee said:
Evolution is driven towards survival of the species, not the individual.
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Deetee, is that a typo by some chance? Most biologists would say that sentence is 100% wrong.


Deetee said:
So it is not just social insects (which can behave like a single organism and which have non fertile workers) which can benefit from this strategem, but other animals too.
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Correct, if they are close relatives. In essence, animals appear to behave altruistically towards close relatives, but this can be seen as selfish behaviour from their genes' POV. This does not support group selection. It supports gene selection.
Deetee said:
Think of the meerkats which take turns acting as lookout for their colonies - the lookout has a higher chance of falling prey to a hawk/other predator, but their behaviour and sometime sacrifice benefits the other individuals in the group, and genetic information which favours this type of behaviour will be preferentially naturally-selected.
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Yes- if the individuals so helped to breed are carrying the same genes as the sentry. If not, then his gene line ends with a sharp squeak!

The social insects have rather different genetics from mammals, which greatly complicate the arithmetic, but the principle holds. It also explains why some mammals and birds, themselves sexually mature, forgo breeding to help their parents raise a new clutch /litter of younger siblings.

A good book on this as applied to humans is Matt Ridley's "Origins of Virtue".
"The Selfish Gene", by Richard Dawkins, is indeed excellent on this , as others have said.
 
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It is also worth noting that European honey bees do not attack enmass but rather "line up" and attack one by one until the intruder is driven off or killed. This limits the number of deaths that occur.
I have seen footage of Giant Wasps in Japan using this, so that a handful of wasps managed to slaughter every bee in the nest.
 
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