SHB and Winter

[BjornBee]

This past fall, I acquired couple of dead out hives and placed them outside beside my garage. These dead outs have SHB larvae and coccoons. (And yes, I know the difference between SHB and wax moth larvae)

I have been waiting for a cold spell, to do some testing. The past couple nights have been in the teens. Last night was 16.9f Its been below freezing for some time, but this is the coldest so far.

Today, I decided to open a few coccoons and retrieve some larvae. These have not yet pupated fully. The frames were frosty with ice and were frozen throughout. I placed the worms in a jar and took them inside the house. Anyone want to guess whats now crawling around inside the dish? Thats right SHB worms.


I was not too nice when I openly said some of the researchers were full of it when it was suggested that SHB needed to pupate in the ground. Since then, others have confirmed my observation of the SHB pupating in the hive and other places. I have also been questioning the consensus about northern winters and cold, dealing with the SHB. I have stated previously that the beetles will adapt and northern cold will have a smaller and smaller inpact in the SHB's ability to overwinter and thus they may inflict increased damage in the future. I admit the winters may have a knockdown effect and a break in the cycle may also limit the SHB numbers, but I also believe that the SHB will adapt and could potentially be a larger problem in the future.

I will continue to test throughout the winter, but it seems that below freezing temps and frozen comb and frames are not a problem for SHB surviving to fight another day.

[Brent Bean]

Great! :( just when I thought that winter would be a stopping point to the latest pest of honeybees. Just goes to show you nature always finds a way to survive.

[Mike Gillmore]

I'll second that, Brent. I've been procrastinating on researching SHB believing we are outside of the danger zone in the cooler northern climate. Guess its time to wake up and get with it, before the tidal wave comes rolling in.

[Wee3Bees Apiary]

Well I'll be . . . that's not good news. I knew that could pupate anywhere (especially in the hive), but I really thought that the winter got the eggs and larvae outside the cluster.

I guess my annual squishing rampage in January February with SHBs needs to continue as there are not many beetles during that time and easily killed because I think they move a little slower then.

[Bizzybee]

Isn't that just wonderful news! Thanks Bjorn! Yeah I know, don't kill the messenger. smile.gif

I don't doubt the worms can make it in the cold weather. I was playing with some I found earlier in the year. I was checking what it might take to kill the little buggers? I finished with straight Chlorox. Nope, it didn't work either. They swim quite well in it. So, that only left old trusty Mr. Hive Tool. Even that took a little work! Those things are built like tanks!

I kept tabs on them all year pretty well. I was fortunate enough not to loose any bees to them. Most of the hives were fairly aggressive with them. And a handful of them would allow them on the frames with them. Needless to say, they had the highest numbers. But I never saw more than about 30 in any colony. The Carnies were on average, much better at fighting them than the Italians. But that isn't to say that all the Italians didn't fare well. I was in the hives yesterday (isn't GA great!) smile.gif and saw very few to none. And the same held true, the same hives during summer with the highest numbers, still have the highest. I took quite the delight in squishing em Wee3!! smile.gif

But, I can say that the hives that had not let them near the cluster earlier, did have a few there now. And I saw none hiding in the wings as they were in warmer weather. I guess it may be that the adults are not nearly as hardy as the larva?

And so.........the fight goes on.

Good Luck Folks! Hopefully we can find a good way to deal with these things. I'm for one, hoping that the bees adapt as well as the beetles do!

[tecumseh]

well at least the cold weather makes the adults move slow enough so that I can squish the little buggers.

I would also think that the length of freezing time would be of considerable importance. at least this seems to be important in halting wax worm infestation. in addition to this 'factor' how the frames are stowed (when frozen) is of considerable importance.

[BjornBee]

I'll continue to see how they survive thorough the rest of the winter.

One of the things I am amazed with the SHB is that they smash very easy for a beetle. I am hoping that this "soft" outer skeleton, will aid in the bees ability to handling/killing/ etc., them.

[dickm]

I asked at an ABF meeting if the beetles would survive a northern winter. The answer was "Yes." The reasoning was that they would be in the cluster getting fed by the bees. You do remember that the bees will feed them? A second point. "Pupate" is not something that results in a worm. Perhaps the rest of the metamorphasis needs the sandy soil. It's a hope.


Dickm

[BjornBee]

Yes Dick, I remember the feeding part. I have mentioned it several times for a good while here on beesource.

What could possibly be needed for the final change into a beetle, that would in the sandy soil versus anywhere else?

[dickm]

>>>What could possibly be needed for the final change into a beetle, <<<

I don't know. It doesn't seem likely they would go to ground to do it if they didn't need to. Nature is usually cheap in this regard. Why wouldn't they do it in the hive if it weren't in some way riskier?

Dickm

[Kieck]

[Sorry, double post. My computer told me it timed out, the message I typed disappeared, so I re-typed it and re-posted. Then the original was here, after all.]

[ December 14, 2006, 04:20 PM: Message edited by: Kieck ]

[Kieck]

"This past fall, I acquired couple of dead out hives and placed them outside beside my garage. These dead outs have SHB larvae and coccoons. (And yes, I know the difference between SHB and wax moth larvae). . . .

. . .Today, I decided to open a few coccoons and retrieve some larvae. These have not yet pupated fully. . . ." -Bjorn Bee

Um, I DO have to question your ability to distinguish SHB from wax moth larvae, Bjorn. See, like all beetles, SHB don't spin coccoons. They pupate "naked." In other words, if you were "opening" the "coccoons" of SHB pupae, you were skinning them. Even SHB can't survive being skinned.

Also, to clarify another matter, "pupation" is a physiological state. Once insects begin pupation, they can not, under any circumstances, go back to being larvae. "Larvae" will not come crawling out of pupae, unless the larvae happen to be predators/parasites feeding on the original pupae.

SHB may or may not be able to survive winter weather. I haven't found any maps of their native distribution to see how much winter they have been able to handle in their native range. Withstanding a few days of below-freezing temperatures is considerably different than surviving weeks of unbroken, freezing temperatures, or periods of freezing and thawing, or deep, sub-zero temperatures.

[ December 14, 2006, 04:20 PM: Message edited by: Kieck ]

[tecumseh]

kiech sezs:
Um, I DO have to question your ability to distinguish SHB from wax moth larvae, Bjorn. See, like all beetles, SHB don't spin coccoons. They pupate "naked." In other words, if you were "opening" the "coccoons" of SHB pupae, you were skinning them. Even SHB can't survive being skinned.

tecumseh replies:
casually I would think that determining the exact 'species' of insect at the larvae or pupae stage would be more than a bit difficult to determine??????

[BjornBee]

Kieck,
Coccoon is defined as (1)the silky case in which the silkworm involves itself when still a larvae: (2)the envelope of other larvae.

I certainly had to look that up since I am not an expert in beetles. I simply call the "casing" a coccoon. Thought it was correct.

Since you seem to know a little about this matter, can you answer any of he following? I can not seem to find answers myself.

What is the lifespan of the SHB?

How long does a larvae exist prior to becoming or even starting the pupation process?

How long before a larvae becomes an emerged beetle? And does cold slow down the SHB or any other larvae from continueing the process? Can larvae survive longer in the cold, waiting til warmer weather to continue thier full changeover?

One of the interesting things, is that I also have wax moth "larvae" that have been in coccoons for a good period of time. I can also open these up and have them crawl around upon warming them up. So as you commented, I am sure they have not really started the passage to pupation from the larvae stage. Although they have been coccooned for some time. I am thinking the cold weather delays this reaction, since it seems that they have done little in over two months of being encased in a coccoon? As with the SHB, the wax moth larvae seem to be in the larvae state for a considerable period of "inactivity", void of starting pupation, to the point that the larvae can still crawl once retrieved.

Your inability to find a map of SHB natural range is understandable. I can not seem to find answers to the most basic answers at this time. Thats why I am playing around and making observations and passing them along to others. I am sure some of my statements will not be 100% correct. But by throwing these items out here, others can add, change, and hopefully all can benefit. Seems there is alot to learn at this point.

[BjornBee]

For those who have not seen SHB larvae as compared to wax moth, the differences are very clear.

The SHB larvae is smaller than the wax moth larvae. It(SHB larvae) is a more "yellowish" color with more distinctive ridges along its body, and moves much faster. I kind of think the SHB larvae is more of a mealworm type looking larvae as compared to the plumper and softer wax moth larvae. The SHB larvae is more opaque than the wax moth larvae.

Both SHB and wax moth larvae have three sets of legs behind the head. The difference is that the SHB larvae, is void of the matching sets of legs that continue down the length of the body, as the wax moth larvae has.

[tecumseh]

bjorn sezs:
The difference is that the SHB larvae, is void of the matching sets of legs that continue down the length of the body, as the wax moth larvae has.

tecumseh ask:
so this would seem to be the distinguishing characteristic???? larvae size would seem to me to be an inadequate determination???? since 'wax mouth' is a general term that represents a lot of different moths. futher it is my 'understanding' that a meal worm is a wax worm.

[Kieck]

Tecumseh:

Identifying larvae is much more difficult than identifying adult insects. Few taxonomists have worked with larvae; fewer still have worked with pupae. Identifying unknown pupae to the species level can be almost impossible.

Most "experts" recommend allowing pupae to complete pupation, thus emerging as adults. As adults, they can be more readily identified.

However, general trends do hold up among larvae and pupae. Identification of larvae (and usually pupae) to order and family is usually possible.

Bjorn:

I have to correct the statement I made yesterday. I said that "all beetles" do not spin cocoons. That is incorrect. Some species of beetles do complete pupation in cocoons.

The distinction between the two, I think, is different for a "lay person" than for an entomologist. Entomologists use the term "cocoon" for the silk casing spun by some insects to protect themselves during pupation. "Puparium" is another term, often used to describe the, usually earthen, chamber in which some insects pupate. Typically, insects that create an earthen puparium do not spin cocoons.

That, perhaps, is the biggest hurdle SHB will have to overcome to go from pupating in soil (earthen puparia) to pupating in hives (cocoons or exposed pupae). I'll be honest, I'm not sure how well developed the silk glands (if they even have them) are in SHB larvae.

As far as wax moth larvae emerging from "cocoons," those silken chambers are cocoons in a way, but not created for pupation. Many of the Pyralidae (the family of moths that includes the wax moths) construct protective cases as larvae. Wax moth larvae can also build protective cases, especially if conditions get tough for the caterpillars.

OK, so for life cycles of SHB as I've read (no first hand experience yet, thank goodness):

Eggs hatch in 1 to 7 days, usually hatching after 2 to 4 days.

Larvae are active for 7 to 20 days, perhaps longer in some instances. Most larvae complete their development in 10 to 16 days.

Pupae take 15 to 60 days to complete metamorphosis. No reference that I've seen has listed anything longer than 60 days.

Adults can live up to 6 months.

In short, the complete life history of an SHB could take place in as little as 23 days. Usually, though, the time from egg to adult seems to take between 33 and 48 days.

I would expect cold weather to slow down development to a point. If SHB have adapted to overwinter as adults, though, freezing weather will likely kill the larvae.

If the ground is frozen, the larvae likely will not be able to create puparia. Without puparia, the pupae are exposed and prone to predation and dehydration, as well as freezing.

I've never tried measuring soil temperatures under a hive during the winters here. Has anyone else tried it? Does the soil immediately under a hive freeze during the winter?

My guess, if SHB larvae came out of cocoons, was that they were seeking refuge in a wax moth cocoon. I'm interested in reading your observations, Bjorn. I'd like to take a look at some of the larvae you're finding, if you'd be willing to send some my way. PM me if you'd like, and I'll get you an address where you could send them.

Oh, one last clarification: typically "meal worms" are the larvae of darkling beetles (Coleoptera: Tenebrionidae), and "wax worms" are the larvae of wax moths (Lepidoptera: Pyralidae).