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dmehl808 Profile
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The difference between bees and hornets


Tere, why is it that bees have barbs on their stingers but hornets and wasps don't? Why should bees (which are "useful") die after stinging, but hornets which are less social/communal and more aggressive be able to sting repeatedly and live on?
Oct/10/2009, 3:46 pm Link to this post Send Email to dmehl808   Send PM to dmehl808
 
Terreson Profile
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Re: The difference between bees and hornets


Oh thanks, Dave, for a fun topic. Here is what I think is right.

First off, in the nomenclature a worker bee does not have a stinger. She has a thing, a noun, called a sting. Now let me go back some.

Honey bees evolved from ancient wasps. It is likely that, again anciently, their stings were sans the barb. If so it is likely that the barb developed as an evolutionary trade off. The barb keeps the sting embedded in the skin. The musculature of the sting is like a pump that continues administering the venom even after the sting has broken off, eviscerating the bee. This means that the animal stung continues to receive the venom until the sting is drained, thus enhancing the defense.

Highlighting this is the fact that the queen bee's sting is without the barb. Since she only uses it when she is fighting another queen bee it makes sense she should need to sting repeatedly in order to maintain her possession of the colony. Not a pretty sight when two queens quarrel. It is to the death of one or the other.

Maybe here is something else. My sense is that a worker bee "weighs" the danger and so "decides" whether or not to sacrifice herself. When I feel a worker on my hand, wrist, or forearm my skin can, so to speak, read her intentions. A worker who happens to light there is not agitated. I'll look down and she is just walking around. A defensive bee will move with agitation. Her feet movements are jerky. Sometimes I'll look down and her abdomen is rising and falling. It is almost as if she is trying to decide if the intrusion is worth her life. Of course there are those workers who've already "decided" on a course of action and sting on contact.

Something else comes to mind. Wasps are carnivores. They sting to eat. Honey bees are not carnivores. They sting only in defense of the colony. Again I figure the barb came as an evolutionary trade off, one made in order to better defend the colony.

Colony defensiveness is a rum thing, except that it is all a matter of genetic imprint. I have a couple of colonies so hot my hands tremble every time I have to go into them. Then last week I was in two colonies, with queens from Hawaii selectively bred for their lack of defensiveness, so gentle I could have lain down with them and fallen asleep.

Tere
Oct/10/2009, 5:44 pm Link to this post Send Email to Terreson   Send PM to Terreson
 
dmehl808 Profile
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Re: The difference between bees and hornets


ah, so you see it as a greater defensiveness, because the venom continues to be pumped into the attacker, even though the loss of the worker occurs, because in colonies there are more workers and thus they are dispensable? Perhaps the lack of a barb is one thing that makes hornets and wasps more aggressive and less cautious. and the factor of being carnivorous. It was fascinating to consider that bees weigh (intellectually?) the risk and sacrifice. You think they know that they die when they sting? How much of it is risk assessment, and how much is instinctual. I believe animals are smarter than we give them credit for, but at the same time all this comes as a revelation.

All of that was very interesting. Where I presently work (a landfill) the hornets and paper wasps are plentiful and aggressively problematic, perhaps in part because of the colors of the vests and hardhats we wear. For some reason the question occurred to me. Thanks for the thoughtful response. Your answer didn't disappoint.
Oct/11/2009, 3:36 pm Link to this post Send Email to dmehl808   Send PM to dmehl808
 
Terreson Profile
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Re: The difference between bees and hornets


You're welcome, Dave. It is a fun topic. I can't speak for hornets and wasps but your mention of the colors of vests and hard hats brings something to mind about bees. Bees are acutely visual, perhaps more so than humans. Also, tests have shown they are more inclined to react defensively to dark colors than to lighter colors. I've noticed as much myself. Last week there was a bee that kept circling me, keeeping close to my veil. She was clearly agitated. When I would pull out a red kerchief to wipe the sweat off my brow she would go after it, damn near bouncing off of it.

Not wanting to anthropomorphize, I still find bees very intelligent. And adaptable, which, itself, can be taken as a sign of intelligence. For example. Everyone knows that the tasks bees see to are age determined. Younger bees nurse the brood, clean house, tend to the queen. Older bees guard the entrance and forage. But if you take all the younger bees from a colony the older bees will see to nursing and house keeping. Similarly, remove older bees from a colony and the younger bees will start to forage. They must notice something not right, probably by smell. The marvel is that they respond to the circumstance.

Maybe you are familiar with this already. If not here is something to add to your landfill thinking:

http://en.wikipedia.org/wiki/Sociobiology

So if social behavior is to whatever extent biologically evolutionary, why not "intelligence"? And what is the point of intelligence if it does not ensure adaptation? Fun stuff.

Tere
Oct/12/2009, 11:53 am Link to this post Send Email to Terreson   Send PM to Terreson
 
Terreson Profile
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Re: The difference between bees and hornets


Dave, I hope you read this soon enough. I talked to a scientist today about your question and I need to revisit my answer.

The real answer is that nobody knows what exactly accounts for what I'll continue to call a worker bee's evolutionary trade off with respect to her barbed sting. And nobody knows because, even at this late date, the genetic mechanism(s) involved in altruistic behavior is not understood. All there is so far are theories and the observations but without the mechanism explained. I also stand corrected with respect to the barbless feature of stings belonging to wasps, hornets, and queen bees. In all cases the sting has a barb. It is just that it is further up or further back on the shaft, which allows them to sting repeatedly without evicerating themselves. And so still for some, possibly altruistic, reason there seems to have occurred an evolutionary trade off, with a worker bee's barb moving further down on the sting in order to embed it in an animal's skin.

Here are two Wiki articles that might interest you. One on altruism and the other on a concept associated with E.O. Wilson's notion of sociobiology called eusociality.

http://en.wikipedia.org/wiki/Altruism_in_animals Take note especially of the term kin kin selection.

http://en.wikipedia.org/wiki/Eusociality

In both cases geneticists have only descriptive, not explanatory language.

Tere
Oct/13/2009, 6:14 pm Link to this post Send Email to Terreson   Send PM to Terreson
 
GaryBFitzgerald Profile
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Re: The difference between bees and hornets


Well, I think the answer to this question is quite simple. Wasps and hornets, as Terreson noted, are carnivores. Bees are social. A carnivore is, by necessity (stalking and hunting), a loner. They function only within their immediate family: the lion’s pride, the wolf pack, the Killer Whale pod, the wasp’s nest. They must hunt in order to survive and return with their prey to ensure the survival of their own genes. Bees, on the other hand, are social animals. They must sacrifice themselves for the good of the colony and, therefore, ensure the survival of their own genes. This is why a human soldier will sacrifice himself for the good of his country…it is, genetically speaking, for the greater good. This is the basis of Sociobiology, that the origins of altruism are genetic in nature. The value of an individual is based on the value of its genes. The carnivore’s immediate family, and therefore the gene pool, will benefit from the food a loner brings home…the offspring will survive. The genes of the social animal will benefit from the sacrifice of the individual required to protect the greater society, i.e., the gene pool…so the offspring will survive.
Oct/14/2009, 11:48 pm Link to this post Send Email to GaryBFitzgerald   Send PM to GaryBFitzgerald
 
Terreson Profile
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Re: The difference between bees and hornets


Sure, Gary. That is the theory and, as such, descriptive of the behavior observed. For a geneticist, however, it is a little less than satisfactory. She will not be satisfied until she finds the QTL, the marker, showing the allele accounting for the behavior. Of course it can be argued that genetics does not account for all animal behavior. On the other hand, E.O. Wilson's sociobiology suggests otherwise.

Fun stuff isn't it?

Tere
Oct/15/2009, 6:20 pm Link to this post Send Email to Terreson   Send PM to Terreson
 


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