OK, could everybody interested in a pissing contest on how they understand evolution better than anybody else please take it to GD or somewhere? Because if I read one more simple-minded reflex-triggered rant on how genes don’t plan or some other such regurgitated catchphrase I’m gonna become a creationist out of spite.
Thanks to everybody else trying to give an actual answer to my question.
So, you want an explanation of the phenomenon of why evolution has produced a particular effect, that does not involve any explanation of how evolution works?
The question assumes that the absence of individual survival is an evolutionary “mistake” of some sort, and asks why it doesn’t change. The answer is that individual survival has insufficient benefit to affect the survival rate of a hive, or the success of the species.
The death of any of the non reproducing bees in a hive has no detrimental effect on the species. The ready visual reinforcement to predators of the danger of failing to avoid bees has an obvious behavioral benefit to the species. As a consequence of this, bees which hang by their stingers when stinging mammals have reproduced more reliably than bees which do not, until the characteristic became ubiquitous among bees.
There may be biochemical reasons, not apparent without vastly more information. Is that what troubles you?
Tris
Yes.
Do you have a cite for this? Because it’s been mentioned as a possibility a couple of times already and I’m sure the OP understands it, but there’s been other possibilities mentioned as well (such as that the bee sting is designed primarily to kill other bees, which won’t tear out its sting, and they sting mammals so rarely that the sting-being-ripped out is not important enough a disadvantage to be selected against), and no one has yet been able to produce a reliable cite for either possibility.
Pretty much, yes. I’m asking, basically: ‘Species x has evolved trait y. I don’t see that trait to be beneficial; in fact, it appears to me that it ought to be detrimental. Thus, obviously, either I don’t understand the benefits of this trait, or it has stuck around because it is not sufficiently detrimental to impact survival rates. Can you explain this to me?’
You’ve given such an answer later in your post, and others have done so, as well, so it’s not impossible.
There’s a question not unlike this one a few threads down, about why the mammalian scrotum is external to the body, providing us with a readily exposed weak spot most video game bosses would scoff at derisively. The answer, or part of it, anyway, is that sperm needs a consistent temperature to thrive that’s somewhat cooler than our core body temperature – and that this benefit outweighs the obvious detriment. Something like that’s all I’m looking for, and I don’t see that being all that unreasonable.
I had a much longer rant composed here, but scrapped it, seeing how it’s not likely to do much good anyway; but please, if you (general you) still have some remaining need to point out your superior understanding of evolution using regurgitated buzzwords to assert your dominance, feel free to do so elsewhere.
I will try again, with special attention on not using any buzz words. The OP asks a specific question, why has a trait not developed, since that trait would obviously benefit the individual bee, and should therefore be conserved, any time it occurred. This assumes a set of conditions exist for what should happen in evolution.
But the conditions that actually exist are that individual survival is not as great a factor, by many orders of magnitude, than the successful creation of a new generation of the species. The bee in question is overwhelmingly likely to be a worker, and even more to the point a worker in the later stages of it’s life. (More mature bees predominate among the likely guard contingent of a hive.) This class of bees will have no progeny of their own, however long their lives may be. Their deaths have no effect of species survival. Preservation of their lives provides no benefit, and their deaths make resources available to the next generation.
Let us examine a different case. American White Tail Deer in an undisturbed environment will expand their population to the limits of predation, and food supply. This process involves an annual death rate from starvation, and predation on the order of one third of the herd. However, the distribution of such deaths is disproportionate for the sexes. Female deer are more timid, and have a more efficient metabolic use of their body fat than males. The combination increases death by both predation, and starvation among males. As many as half the males in a healthy herd may die every year.
Some of the reasons for this are that males have much higher activity levels, higher muscle tone, antlers, and competition with other males for mates that causes them to spend their energy at a far greater rate than the females. In addition, males engage in behaviors that make them preferentially available to predators over females. None of these characteristics increase the survivability of the individual male deer, but they are conserved. In fact, female deer preferentially select mates based on the higher level of such characteristics, such as antler size, and herd dominance. If that is true, it must therefore be true that female deer that do so have more surviving descendents than females who do not.
Death in higher numbers is a survival characteristic for the herd, if those higher numbers include more dead males. Dying is an adaptation for species survival. If more males die, more females survive. Since one male is predominately responsibility for the genetic contribution to the next generation for a large percent of the herd, a male with these death enhancing characteristics is more successful in producing reproductions of his own genetic code. His daughters will carry the genetic pattern that favors mate selection on that criteria, and his sons will have more of those characteristics that he carries.
The existence of socialization among animals profoundly changes what characteristics are beneficial to the species. The so called altruistic behaviors often debated are sometimes confused with the existence of a decision on the part of the individual animals. If I wrongly attributed that to the OP, I apologize.
Tris
The organism being selected for or against, the reproductive unit, is the hive of which most individual bees are disposable and dispensable parts of.
You might as well ask if it wouldn’t be better if a woman didn’t break of a nail while successfully fighting off a rapist or someone intending on killing her. Sure the nail is a loss but on the scale of protecting the organism and it future reproductive outcomes or potential, inconsequential, And so it is with the individual bees.
I’m sorry, but how you get that from the OP is a bit of a mystery to me. I’m asking how (not even why or anything!) a trait that seems so obviously detrimental has developed, and how it persists. I’m not asking why some trait ‘failed’ to develop or anything like that. Heck, I even acknowledge, right there in that first post, that the individual bee doesn’t directly have anything to do with passing on genetic material. The only thing I’m assuming is that, in general, evolution tends to maximize fitness, and it wasn’t clear to me how the development of the one-way warrior bee meshed with that, so I thought I’d ask. In the future, I’ll know better, so I guess my ignorance has been fought on some level.
So I googled around and found the following:
“The bee’s stinger evolved originally for inter-bee combat between members of different hives, and the barbs evolved later as an anti-mammal defense: a barbed stinger can still penetrate the chitinous plates of another bee’s exoskeleton and retract safely.”
“The barbed stinger is advantageous to the survival of the colony, as only a momentary contact, a fraction of a second on a bare part of a predator, (typically the nose or near the eyes) is required - should the predator crush or brush off the attacking worker it will be to no effect as the stinger is embedded, progressing deeper (due to the sawing motion of its twin barbs) and the venom bulb is actively pumping - all this without requiring the presence of the bee. It will be easy for an attacking bee to find the nose as they are (as are mosquitos) able to sense and navigate to regions with high levels of carbon dioxide.”
RaftPeople
Good job.
I sympathize, Half Man. So far there have been at least three possible explanations mentioned: the loss of worker bees in an attack has no effect on the survival of the hive; the detached stinger delivers more venom than the bee otherwise could; the barbs evolved to help sting other bees, and the loss of the stinger when attacking mammals and birds is a side effect.
The first suggestion obviously doesn’t explain anything by itself, unless it implies that the barbed stinger was just a random mutation that spread through genetic drift (which seems extremely unlikely). However, it is compatible with other explanations and shows why any advantage the barbs provide might be enough to outweigh the loss of workers. It is also worth noting that guarding the hive and foraging are typically the last two stages of a worker bee’s life. Hive building and maintenance, tending the queen, feeding the brood, etc., are all done by younger bees who stay inside the hive.
The second suggestion seems the most satisfactory. The stinger is not only barbed, but also has a mechanism that will quickly work itself deeper into the skin of a mammal or bird after it has been removed from the bee. Only a quick jab, even if not enough to penetrate the skin, is enough to ensure that a dose of venom is delivered. It is not unusual for beekeepers to be stung by singers that work their way through thick gloves after the bee has left.
The third suggestion, from Wikipedia, that the barbs evolved to help penetrate other bees, and that the effect on mammals is accidental, is likely true but incomplete. Yellow jackets and Texas honey wasps apparently have smaller barbs that don’t usually cause the stinger to detach. (Though the cite on honey wasps disagrees.) Based on this, it seems quite plausible that the barbs’ original function was to penetrate chitinous exoskeletons. Nevertheless, the honeybee’s stinger seems specifically adapted to detach from the bee and continue stinging large animals.
Unfortunately, all of this seems speculative. I don’t think you are likely to get a more authoritative cite than what’s been presented.
I forgot to mention that I had my first beekeeping experience this week. For some reason, one hive really hated me. Hundreds of bees attacked and left their stingers embedded in my suit and gloves. (I only got one full-on sting, and that was from impatiently removing my suit while there were still some bees on it - one still had its stinger, which it stuck in the side of my head.) I asked the experienced beekeepers with me if I wasn’t harming the hive by causing so many bees to die from stinging my suit. They said that the number was insignificant compared to the tens of thousands of bees that make up a single hive.
Alan the key of your post is the recognition that these explanations are not mutually exclusive. There is little value to the reproductive unit in preserving the life of a single or even several dozen bees. Any tiny additional benefit to the hive’s survival, and thus reproductive fitness, gained by sacrificing a few dozen workers is therefore to be selected for. Does a barbed stinger that detaches more effectively repel a large potential mammalian threat than an unbarbed stinger that stays on and therefore delivers less venom? It seems that the answer is yes. Therefore the genes that code for that will be selected for because those genes are marginally more likely to be passed on.
Consistent with this analysis is that solitary bees have weak stings that are unbarbed (smooth); they can sting repeatedly and do not die after the fact. I suspect the same is true in smaller hives in which each bee life is of value. Also queens have smooth stingers.
You started a discussion in order to have explained to you something that you don’t understand. Part of the reason you don’t understand it is because what you DO understand is not entirely correct. You use phrases like “seems so obviously detrimental” as if that means “is a universal and unquestioned fact.” And then you insist that this is the only basis on which you’ll allow the discussion to proceed.
You’ve asked a question. Don’t dictate the answer; or else why did you bother to ask?
You’ve been given a great deal of excellent information in this thread. Your question has been answered and explained several times, in several different ways. To insist that it somehow be rephrased in order to keep your original assumptions intact is not reasonable.
It’s a pretty safe starting point to assume that bees that are alive are more valuable to a hive than bees that are dead.
What is interesting about this question are the specifics (not vague generalities like that’s how nature works) regarding the fact that in this case sacrificing bees turns out to be a decent strategy for the hive. What are those specifics and how did it come about? That is the point of the thread.
Except when it’s not.
Is it really your contention that the best way to discuss an issue is to begin with an assumption and absolutely refuse to examine it?
However, Half Man Half Wit’s question is an entirely reasonable one. The death of workers, even if they are sterile, potentially could have an effect on colony survival, and thus the ability of the reproductive individuals to pass on their genes. While it is possible that the trait of dying after stinging could be entirely neutral and have no effect whether or not it is passed on, it is more reasonable to ask what the possible factors are that have promoted it’s evolution.
But it is probably a pretty safe assumption here.
Colibri, your irrational bias against me is well documented, but you’re mostly pretty good at keeping out of GQ. Mostly.
It’s been explained over and over again in this thread how the sacrifice of a single worker bee benefits the hive as a whole, and thus serves to pass on the sacrificed bee’s genetic material indirectly through its close relatives. One of the clearest examples of “altruism” as a successful evolutionary strategy. So quite clearly, in this context, it is the very opposite of a safe assumption: it is quite simply wrong. Have you read the thread at all?
Sorry, hadn’t seen this.
Again, you’re talking about perfectly reasonable starting assumptions–hypotheses–but this thread has become an exercise in refusing to examine them, let alone, rethink them, when they don’t fit the facts. It’s reasonable to ask, in other words, as you say; it’s not reasonable to refuse to listen to the answers.
But at least my entering into it made it easy for you to choose a side. :rolleyes:
So you think it’s not a pretty safe starting point to assume that bees that are alive are more valuable to a hive than bees that are dead. Ok.
Wait. I thought that it wasn’t a pretty safe assumption.
Maybe it’s a “perfectly reasonable starting assumption” but it’s not a “pretty safe starting point to assume”.