Worker bees take off (disappearing honeybees)

Billions of bees have done just that, leaving the crop fields they are supposed to pollinate, and scientists are mystified about why.

The phenomenon was noticed late last year in the United States, where honeybees are used to pollinate $15 billion worth of fruits, nuts and other crops annually. Disappearing bees also have been reported in Europe and Brazil.

Commercial beekeepers would set their bees near a crop field as usual and come back in two or three weeks to find the hives bereft of foraging worker bees, with only the queen and the immature insects remaining. The worker bees that survived were often too weak to perform their tasks.

If the bees were dying of pesticide poisoning or freezing, their bodies would be expected to lie around the hive. And if they were absconding because of some threat -- which they have been known to do -- they wouldn't leave without the queen.

Since about one-third of the U.S. diet depends on pollination and most of that is performed by honeybees, this constitutes a serious problem, says Jeff Pettis of the U.S. Agricultural Research Service.

"They're the heavy lifters of agriculture," Mr. Pettis said of honeybees. "And the reason they are is they're so mobile, and we can rear them in large numbers and move them to a crop when it's blooming."

Mr. Pettis and other analysts have gathered outside Washington for a two-day workshop that started yesterday to pool their knowledge and come up with a plan to combat what they call colony collapse disorder.

Bees are not returning to the hive. They get lost. Why? Bees use sunlight to navigate.

Measurements of the interommatidial angle (Δφ) and facet diameter (D) of the same ommatidia in a number of insects and crustaceans with large eyes have been related to the effective intensity at which the eye functions by the following theory. The highest spatial frequency which the eye is able to reconstruct as a pattern is limited by the interommatidial angle Δφ, which is the sampling angle, because two ommatidia are required to cover each cycle of the pattern. At the same time, the absolute modulation of light in the receptors caused by the pattern depends on three interdependent factors.

(a) The theoretical minimum angular sensitivity function, which has a width of λ/D at the 50% level. The wavelength λ is taken as 0.5 Î¼m. This component is not only the limiting angular resolving power of the lens: it reduces modulation caused by all patterns, with greater loss at higher spatial frequencies. Larger lenses increase resolution and sensitivity. (b) The effective light catching area of the rhabdom. This is the angular subtense of the rhabdom area (the receptor) as seen in the outside world (i.e. subtended through the posterior nodal point of the lens), and is the equivalent of the grain size in a film.

Since we now know global warming (yep, it ties together) is due to changes in the intensity of the sun and a (+)change in energy at certain wavelenghts.

How can the bee disappearance be overlooked as positive proof that solar radiation is the (primary) cause of global warming?

Here's an interesting quote from the linked article;

"...There have been other fluctuations in the number of honeybees, going back to the 1880s, when there were "mysterious disappearances without bodies just as we're seeing now, but never at this magnitude," she said..."

Haunting [these last few months] the Bee-L listserve discussion board hosted by the UNY Albany, I've seen more than a few of the long-time commercial beekeepers mention this.

Another little factoid associated with some of these bee disappearances, is that other bees colonies, hived in the same yard wouldn't "rob out" the abandoned hives, for a week, or perhaps two. This was noted as other than normal, though "robbing" characteristics can and do vary to an extent among bloodlines, or lineages of bees. It suggests something about the hives, or the stores didn't "smell right', which may have been the reason the bees left, en masse, (though NOT "swarming") in the first place.

I do wonder what the temperatures were during this time of absconding (leaving, disappearing), and the time it took other bees to discover the "loot" in hives abandoned in the same yard. Though with all this reasoning, and the line of questioning and pondering it produces in mind, in light of normal honeybee behaviors, there remains still the question, where's the queen? They are finding hives COMPLEtely empty? If foragers went through a time of brief warming, a 'false spring', then maybe some of them could have left, and been unable to make it back. If there was something causing die-offs while in winter cluster, there would be dead bees there, to indicate it. Though honeybees do 'swarm' when there is a nectar flow on, and the hive is getting crowded, they leave behind a good portion of the bees, along with capped brood, including multiple queen "cells", when they do so. And it's unheard of for bees to swarm after a period of dearth! it doesn't happen...

Of all the "disappearances", none have been referred to by "bee" folks as classic "absconding", for what it's worth. Though it does resemble in many ways, the absconding traits of one of the "african" races of bees, though the time of year is damn peculiar for absconding.

Other reports have some of the big disappearances occur AFTER the migratory move to California in early March, for almond pollination.

Then we've had some gal (whom i cannot recall either the name, or qualifications of) recently testify before congress, sharing that she thought there a link to this "CCD" [a.k.a, we don't know WTF it is] and a few different fungus.

The French beekeepers had an experience recently with a "systematic" herbicide/pesticide(?) marketed there under the tradename "Gaucho", and in their case, were able to prove it. So far, the conditions don't appear to be identical enough to warrant anyone being able to safely (or should I say "accurately") pin the blame on systematics, or "nicitoids", as I've also seen them referred to.

In the French cases, these nicitoids, it seemed to be strongly indicated, interfered with the bee's orientation abilities, causing them to become unable to find their way back to the hive, and thus die. If enough bees die before their time, then the hive can't keep up, in raising more brood. Though individual bees live 6 weeks or so during their prime and busiest season, they don't hatch out knowing how to forage for nectar. Besides, when they are newly hatched, they have other, also crucially important hive chores to do. It's the middle aged, and elderly among them that do most of that portion of the foraging work.

Hives wintering over, can have bees live for many months, since they are mainly at rest, moving only to 'shiver' to build up heat in cluster, or move slowly over the combs, venturing onto combs holding honey and pollen stores, to take back to the cluster (if not moving "in cluster", en masse, if they can) but sometimes they cannot even do that, and can starve in winter, even with honey stores in the next super up, since they have to break cluster to get at it. When it's cold, they don't want to, really can't afford to become separated, since it's the collective heat of all of them, that keeps it warm enough (somewhere above 40 degrees F, if memory serves).

Swiss researchers have found 5 different viruses present in hives. Some hives would have one, or two. Some, all 5. How these viruses affect bees, if it is known, certainly isn't widely known...I've been searching.

There has been in (fairly) recent years, trouble with (first, it was) tracheal mites, then the varroa mites, along with various fungus, brood diseases, and other past, somewhat rare, pesticide induced die-offs. With the pesticides, the evidence is clear enough (usually), though there are some various plant and blossom treatments which could find their way into pollen stores in the hive, and show up, mainly "later", than when they were first gathered. So far, direct pesticide contamination has been ruled out. That may change, but I'll not say here, that it WILL, or even SHOULD.

It's been broached by some, that the varroa mite can weaken the bees enough, for them to become more susceptible to either viral or fungal infections, or a combination of both. It's been mentioned by others that they are suspecting tracheal mites to be still a strongly possible cause...in part...because since the arrival of the varroa mite (from an Asian bee), attention has been diverted towards controlling varroa, and in some cases, perhaps resulting in less attention to the tracheal mites, since one cannot SEE the tracheal mites, except by careful dissection of the bee, and the use of a good microscope.

Whatever it is, large scale, widely experienced bee die-offs are not brand-new news. Even if this latest one, if there really is such a thing as this CCD, is from brand new causes.

Soy proteins can be a problem, if the soy isn't properly "toasted" (I kid you not). Soy might harbor systematics, too. Since I'm not large scale commercial, I think I'll try to avoid soy altogether...even though it does appear that there are some pretty good supplemental honeybee feeds available which contain soy proteins, that by (most?)all accounts, have been used safely.

HFCS (high frutcose corn syrup) though delivered to bee yards literally by the tractor-trailer tanker load, I harbor some suspicions of, too...how much of this has been GM'd? In what way? And no, typical hybridization does NOT = "genetically modified", so if any lurkers want to jump on that one, expect a filthy and foul freepmail, if you even dare trying going there, with me.

I do hope that enough beekeepers have kept careful records of what they've fed (supplemented) their bees with, [so those inputs can be traced, to look for any possible 'pattern'] where they kept and moved them to [so that careful investigations can occur of the ag lands, concerning use of fertilizer, pesticide, herbicide, and fungicides} and what they, the keepers "treated" their stocks with in the efforts to control the different mites, and keep certain fungus, from ever becoming spores, and thus one of the "old" problems.

Who knows? There might be some subtle chemical reaction between various supplement, treatment, and pesticide/herbicide/fungicides that bees are exposed to while pollinating cotton, soybeans, almonds (the blossoms are treated with various "stuff"), etc.

Meanwhile, it's 5.1 mm foundation, followed by 4.9 mm, for me. If anybody around here knows what THAT means...

"...They get lost. Why? Bees use sunlight to navigate."

We humans "see", what is it, only FIVE percent of the available wavelengths of sunlight? It's does make one ponder & wonder...

To answer your last question, one might need first to link these latest bee disappearances to changes in sunlight--- and that hasn't happened yet -- if it ever will. Not all hives have "disappeared". Not even all beekeepers have experienced "more than usual" winter losses, that they can't see some sign of varroa mite infestation, or some other simpler explaination, like, not enough strength of hive going into winter, not enough well positioned honey & pollen stores within the hive, the added stress of being moved by truck halfway across the country, etc.

Things such as you mention here certainly shouldn't be completely dismissed, out of hand. But folks are looking at other stuff, for the most part.

I did read some interesting tests done concerning how bees orient the direction of their foragings, in regards to sunlight. It makes me want to always be carefull in changing which way a hive entrance points, if the change is going to occur during an overcast period.

If the foraging bees were used to say, turning hard right upon exiting the hive, come the next morning, they'll do the same. If one moves the hive, say to the other side of a field, and points the entrance in the opposite direction, what WAS "hard right", now becomes 180 degrees opposite.
On an overcast day, the bees will keep going the same routes, coming from, and in relation to the hive they oriented with during sunny days...unless they can find forage in this "new" but old direction, they wander around half-lost and sometimes have a bit of trouble making it back to the hive, since they use other visual cues, too, and can become a bit confused.

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