Recently I removed all brood and caged queen for a week to eliminate varoa. New foundations were immediately placed for bees to build new comb. During the week (before the queen is release), oxalic acid and sulphate were applied to the colony. The development of larvea were great initailly but when reached days 10 and after, capped pupae were chewed away by their sisters. This only happen for the earliest 2-3 combs. After that, they backed to normal. This problem happened to almost all hives that I imposed the same procedure. Why this happen? Could this due to the eggs that stored in the queen turned "bad" because she was suddenly forced to stop from laying eggs?
Capped pupae are generally chewed away by the other bees when the larvae inside have died. They are housecleaning. All have a wonderful day. Cindi
But why they die in the first place? The combs are all newly draw comb.
Chilling is a common happenstance, although I think malaysia is more tropical I can't assume that without being told. What were your temperatures like?
Where they pupated or still larval? Just checking, you mentioned did pupae. Could you tell if they were still alive when chewed out?
I've read that oxalic acid can damage brood. I don't know anything about sulphate's affect in the hive. Without knowing more about your environment and pests I would assume one of the treatments damaged the young bees.
-rick
OA will damage brood. Perhaps these brood were dead and are being removed as a rsult of hygenic behaviour.
Ya'll need to start reading. The brood was removed and the queen was caged. New foundation when the treatment was made. The queen released, started laying and then the chewing out occurred.
Jerrymac: will treatments outright kill, or just damage larvae/eggs? Damage so that the pupation will progress, but damage has been manifested? At which point do the bees realize that the damage will result in an unfit bee?
It sounds like after the caging\brood pulling, 10 days later, after the larvae were capped that this occured. I don't know at what point the treatments occured. He mentioned pupae, so I assume that they had pupated by then. I might suggest AFB but I think that only happens to the larval stage.
If the queen's eggs were damaged then I doubt they would even have hatched.
-rick
So you think there was some residue left in the cells and the queen laid eggs in those contaminated cells?
I find the possibility of residues causing damage to the brood to be somewhat unlikely. From everything I've heard, Oxalic Acid is supposed to have far less residual effects than most treatments. From what I understand, one of it's biggest draws is that the combs will not absorb it the same way they do Checkmite + or Apistan.
No temp problem as here day/night temp above 22C. At first I suspected sulphate or OA left residue or even impregnated in new comb so pupae die in the cell. But I tried on other hives with new comb that cleaned from OA and Sulphate, same problem happened too. The pupae were found die when pulling out from cells.
An interested thing is observed: this only happened for the first 2-3 combs where the eggs were started to lay with eggs after the queen was release. When the 2-3 "problematic combs" were laid again with eggs, no chewing was found and all cap broods were hatched. So this lead me to a hypotesis: the eggs would spoil if they are not discharge from queen body when they are already fully developed.
Perhaps you could try the same thing without any treatment. Just cage the queen a while and then see if it happens again. Did you give the queen an OA treatment? Perhaps on another experiment treat a queen, cage her for awhile and then release her in untreated hive. Might get so interesting results.
As every has said, the bees chew out pupae when they sense something is wrong with it, like it's infested with a disease or mites of some kind. I don't have a clue what that would be. Chalkbrood, Sacbrood, EFB, AFB, Parafoulbrood, or any other brood disease would cause this as would Varroa infestation with hygenic bees.
Would try to conduct more experiments as what Jerrymac suggested. Any interested outcome will let you all know.
Many thanks for opinions.
Recently I split my hive and introduced some new queens from Autralia, suprisingly I found that some hives happened the same problem too, where large number of pupae were pull up from cells before they are hatch. Very important phenomena that I observed was it only happened to the first 1-2 combs where queen starts laying eggs immediately after they were released from cage. Mite infestion is unlikely as the subsequent pupae hatch successfully without any treatment. So, again, queen doesn't lay 'good' agg immediately after long time caged?
limyv. So, that sounds like a very probably hypothesis, considering the same thing occurred again regarding the queen being caged, and so on. Good that you followed up on this post. Have a wonderful day, good health. Cindi
I would guess, from the initial posting, that there was still Oxalic acid still present in the hive to the degree that it affected the eggs laid after the queen was released or at a level that affected the larvae/pupae that was returned to the hive. In either case it is good positive hygenic behaviour. If I were to repeat such a treatment I would wait a longer period before releasing the queen or returning the brood.