Queen cell hatching

[alancooper]

Using the Ben Hardin method, I recently grafted 15 larvae into cell cups. Eleven of the grafts formed good looking queen cells that were transferred to hair curler cages and kept in an incubator. Of the three queens that hatched, two died after a couple of hours and one survived. grafting was straightforward from healthy bees and incubation conditions were good. Can anyone suggest likely reasons for the failure?
Alan.

[Jon]

A virgin queen which emerges in an incubator need to feed immediately or it will be dead in a few hours.
Put a little food in the bottom of the roller, a fondant honey mix will do.
You could also put a couple of nurse bees in the roller if she is going to be in there for a few days.
The critical period for development is the 4 days after the cell is sealed when the larva is pupating.
If there is chilling or rough handling during this period you will lose queens.
Transporting from the Cell raiser to the incubator needs to be done quickly and carefully if you move cells just after sealing.
I usually move mine to the incubator 2-3 days before emergence when the cell contents are much more resilient.
The other thing you should do is flatten the queen cell she has emerged from so she cannot go back in.
A hungry queen goes back into the cell head first looking for remnants of royal jelly and dies of starvation inside.
You should be getting 13or 14 queens emerge from 15 cells so the problem is with chilling, transport or humidity level in the incubator.
You need to make sure the water trays are kept topped up.

PS Alan. I presume you are one of the queen rearing group Willy Blakely is advising in Fermanagh.

[alancooper]

Jon,
Yes I am part of the queen rearing group. Willie gave us excellent advice (he covered most of your points) which we have followed for the last six weeks or more but I have not recently contacted Willie. We have raised some fertile queens already but our success rate is low - we have put this down to our "learning process". From the grafting to the emergence stage our success rate has been around the 20-50% mark. Your advice has highlighted "transport" as a possible cause (your other points are OK) - ie., we have been taking our incubator home from the apiary by car (20-40 min or more of careful driving). We will now probably leave the incubator in the apiary to test if transport might be the cause.
Thanks for your advice.
Alan.

[Jon]

Why not leave the cells to day 10 from grafting before moving them?
Hi Alan
The queens are fully formed at that stage and will not be harmed by jolting or chilling unless it is excessive.
I move cells from colony all the time at this stage. I put the rollers on them and put them in my rucksack and cycle home from the apiary.
An hour out of the colony does them little or no harm at this point.
Humidity in the incubator is also important. If the humidity is too low the cell wall dries out and the queens fail to emerge.

Willy B will keep you straight. I work with him a lot through the NIHBS stuff.

[alancooper]

Jon,
Last night we opened the unhatched queen cells. Most had dead, late-stage (dark) but small Qs inside. Some cell lids showed signs of chewing. We speculated that that there not been enough royal jelly - and will be grafting again.
Say hello to Willie for me.
Alan.

[Jon]

You sure the humidity level in the incubator is high enough?

[fatshark]

I have no means to measure the humidity but suspect it would be difficult - particularly in a homemade Heath-Robinson setup like I use - to make it too high. I have an ice cream container containing a litre or so of water adjacent to the caged cells and usually get an acceptable proportion emerging. However, I have less success with introducing (or keeping alive*) virgins, so prefer to use them as cells.

* and pretty much abject failure keeping virgins alive, caged, in a queenless colony.

[alancooper]

You sure the humidity level in the incubator is high enough?

Jon,
Yes - water was always in the bottom of the incubator (a new one) and the electronics gave high humidity and optimum temp readings. Plus a small amount of honey in the bottom of the curler cage.
Thanks for you comments.
Alan

[Jon]

fatshark, the virgins seem to be fine in a roller cage in the incubator for a few days as long as they have food.
Even better if you put in a few attendants.

[Jon]

Alan, are you using the Brinsea Octagon Incubator? Most of the queen rearers have that one.
I have one of those and have been getting good emergence rates but I always move the cells to the incubator late on in development.