Dieing or not dieing after delivering a sting was not the trait being selected for. Sex organs converting to stinger system was. It’s just tough luck that the results of delivering that sting can be fatal to the worker bee. For the species, the benefits of having a stinger outweighed the negatives of losing the workers who did the stinging, meaning more queens with stinging workers lived to pass on the trait.
The only thing genetics cares about is whether or not grandchildren happen. Stingers that pull out vs. stingers that don’t pull out are probably an irrelevant issue for a hive of hundreds/thousands of members; the only advantage to the latter over the former is that a relatively small proportion of neuter bees survive longer. Since they are not involved directly in seeing to it that grandchildren occur, it’s a non-issue.
In hive insects with smaller populations, it would potentially significantly affect the chance of grandchildren surviving if the neuter guardians died while guarding the hive offspring.
ANY time someone proposes a “reason” for an anatomical difference among animals on the basis of genetics, they are doing nothing more than speculating; genetics doesn’t work by “reason.”
there is no Borg like hive mind at work. though mutations that make survival more likely will often be what you will find. so chance and probability can give what could appear to be reasoning or external causation; people will often refer to the results as having that ability of reasoning or need to be caused.
Pretty much this. The leaving of the venom sack is the key.
An insectivore that sees bees stuck into his body, with an immediate, and obvious pain stimulus is less likely to repeat the behavior of fuckin with bees. That is only a trend, of course, but it is a trend that continues more often for bee predator species. Since nearly 100% of the bees involved in this behavioral interaction are not going to be directly involved in procreation, and almost all of the non bees will, eventually behavioral modifications, both learned, and inherited will favor bug eatin critters opting for non bee bugs as a major part of their diet.
Tris
Umm…well, if there’s something better–a way of stinging with the same effectiveness while going on living, without some other cost–then a new allele specifying the “better way” would take over.
Well, yes and no. There would be selection against needless death of cells in an organism. Loss of workers is a cost.
I think that honeybees are one of the species where this isn’t true, despite their being haplodiploid, because queens mate with multiple males. Also, a worker’s sons are more related to her than her brothers (even without multiple mating, which doesn’t enter into it). In some species, workers lay unfertilized eggs, which develop into males (I think honeybees are one).
But I don’t think that’s qualitatively relevant to the question.
I had a lecture on honeybee genetics last year. I’ll have to dig up the notes and double-check.
Not at all. “Better” is an abstract concept; a human conception. “Good enough to pass on the genes” is the single criterion of natural selection.
Rabbits would be “better” at fleeing predators if they had wings. Hell, if they had jet engines and laser beams. Evolution does not seek out a “better.” It simply fits the organism into the niche it occupies.
Hive bees are so closely related to their sisters that by protecting the hive, they ARE passing on their genes, just not through their own individual reproduction. It amounts to the same thing, and it works.
“If it ain’t broke, don’t fix it.” –Natural Selection
Hmm. Unless my fundamental understanding of such thing is fundamentally flawed, parthenogenesis from a female organism cannot produce male offspring.
That depends on the species IIRC, lissener. “Male” and “female” isn’t defined by “which one happens to be XX;” in general it’s by “which one has the bigger reproductive cell.” There isn’t any reason why a haploid couldn’t produce its species equivalent of sperm, on paper.
Parthenogenesis from a human female, otoh, wouldn’t produce a male.
On paper?
In theory.
Everybody who’s saying that evolution has no intention or goal-direction is right, in principle. But it is, nevertheless, a directed process – towards higher reproductive fitness, up the hills in the adaptive landscape; it is only undirected and equal to a random walk if the adaptive landscape is flat, and no selective pressure acts on the population, so the dominant (or even, only, in the extreme case) mechanism of genotypic change is genetic drift, and every allele’s chance of becoming the dominant (or even, only) one in the population is exactly the frequency with which it occurs within it, in the long term limit. However, generally, the adaptive landscape isn’t flat, and then, evolution (with overwhelming likelihood) acts to maximize the fitness function – the random walk becomes a weighted one, with steps upwards being much more likely than steps downward in the fitness landscape. Given enough time, such a process will always end up ‘atop the hill’, at least, atop a local one; a too deep valley may be too hard to cross, with the costs for reproductive fitness being too high, which is the reason why we probably won’t see any rabbits with jetpacks any time soon, or why there are no wheeled animals. In that sense, yes, there is a ‘better’ in evolution.
So, my question, basically, amounted to asking why, since bees not dying seems to be in every case higher up the hill than bees dying after a sting, bees die after stinging. One possibility is that what appears to be higher up to me isn’t, actually, and there have been some good answers in that direction; another possibility would be that while the ‘more bees surviving’-option does represent a higher value of the fitness function, the costs of getting there would be too high, i.e. there’s too deep a valley in between. Also figuring into all of this is that my assumption was that the bee’s barbed stinger had developed from a previous, smooth version, which would only be reasonable if it had some survival advantage, since, even in a flat fitness landscape, the random walk hitting on this complex combination (with the auto-injecting venom sac and all) seems exceedingly unlikely. However, if the stinger developed in this version from sex organs/egg-laying apparatus, that concern is baseless.
A number of insect species, bees among them, have an XX for female and XO for male, the “O” meaning no second sex chromosome. So females come from fertilized eggs, and males from unfertilized eggs.
In humans, and XO set of genes produces Turner’s Syndrome, and the person is a sterile female. She comes from a fertilized egg, but one missing the second X chromosome.
Other insects use the XY sort of combo vertebrates do.
But just to show another example of “it doesn’t always work like in humans”, among birds XY is female and XX is male, the reverse of our system. (Actually, different letters are used to designate sex chromosomes in birds, specifically “ZW” but you get the idea - in birds females have two different sex chromosomes and males have two identical ones)
So there are several systems of sex determination out there, and admittedly this post is a simplified collection of examples.
Yeah, every time someone asks an Evolution question there’s always a string of “Papa Smurf always says” posts explaining basic facts about evolution to the OP when the OP has given no indication he needs such an education. It’s bothersome.
But I do think you’re wrong about there needing to be some survival advantage conveyed by an evolved characteristic. There just needs to be not enough disadvantage. In other words, as long as the stingers’ being ripped away doesn’t kill too many bees, it doesn’t matter if the ripping away conveys some advantage or not. The advantage is in the ability to sting at all. The ripping away may persist even if it is disadvantageous, as long as it’s not too disadvantageous.
That said, the fact that the sac and musculature come away with the stinger and form a coherent venom pumping machine independently while embedded in the skin seems to indicate there’s some specific purpose for the embedding of the stinger–i.e., that there is in fact some advantage to the whole process.
Now I don’t have a cite right this second but if I am not mistaken, there is an advantage to leaving the stinger that no one has yet mentioned.
When the stinger detaches and continues pumping venom into the victim, it also releases a chemical to alert other bees that the victim is dangerous. The “scent” calls more bees over to handle the threat to the colony.
Another reason you should get the stinger out as quickly as possible.
You’re assuming a certain type of sex-determination system (the type that humans, among others, have). This is just one of many found in nature. Perhaps you’re also assuming that all parthenogenesis produces offspring genetically identical to the mother, which isn’t the case.
In the hymenoptera (bees, ants, wasps), parthenogenesis is the usual way that males are produced (essentially the only way). That’s how their haplodiploid genetic system works. Haplodiploidy is the reason for the atypical levels of relatedness discussed above. This atypical relatedness was proposed to be responsible for the evolution of eusociality by Hamilton in one of the first papers about kin selection.
“Good enough” would seem to be an “abstract human concept” as well, just one that isn’t good enough, much less better.
I’m not really sure what you mean. If your point is that something that seems “better” to us, but doesn’t increase inclusive fitness, will have no selective advantage, sure. If you mean that something that increases fitness by 10% will not be favored if fitness is already “good enough”, then you’re dead wrong.
Well, it’s reasonable to ask why rabbits don’t have wings. A number of answers come to mind, including that the cost would not outweigh the benefits (at least with birds around to occupy certain niches.
Again, I’m not really sure what you’re saying. If you’re saying that a new allele that increased a rabbit’s survival probability at no cost would nonetheless not be favored by selection because rabbits are already doing sufficiently well, you’re wrong.
I’ve got the kin selection thing down (by the way, most “sisters” are half-sisters due to polyandry, and therefore less related than daughters, but that’s largely irrelevant to what we’re discussing).
Dead workers are a loss to the colony, and decrease the (direct or indirect) transmission of its member’s genes. With less worker death, a hive could, for example, get away with making fewer workers, and put the saved effort into making more drones and queens. Genes that lead to making more drones and queens get passed on to a greater extent, and hence, more or less tautologically, are favored by natural selection.
[beejack]Oh dear lord! Bees! - The Something Awful Forums
At this point it was clear these little assholes weren’t getting the message. Their arrival in my sister’s property was an act of agression, and we weren’t going to stand for it. So it was time for some redneck engineering:
[/beejack]