Why did they die so suddently?

[mvanek]

I overwintered two hives, both in 2 deeps.  We had a very mild winter here in MA, but then temps soared into an unheard of 80's in mid March...very early for this area.  The bees were in a healthy cluster with honey left before the warm temps.  The next couple of weeks after the warm temps, the temp went back down to normal for this area (50's during the day and below freezing at night). 

I just went to check on both hives and each had a tiny cluster (about 20 bees) and they were not moving.  They were still on honey stores and there were no pests. 

How did they die?  Don't want to make the same mistake twice...   :-\

Thank you,
Melissa

[AllenF]

20 bees do not make a hive.   No stores?   I bet they were robing the place out.    I bet your bees starved.

[mvanek]

Possibly, but there were none with their heads in the comb and the other dead bees were on the floor of the hive.  This looked like it was the last remaining part of a cluster, trying to keep the queen warm and they were right on top of honey stores.  The queen was still in the middle of the group...

[BlueBee]

Just a guess, but the dead bees might have been formally clustering over the brood and couldn’t get to enough honey stores as your temperatures got back to normal.  As they ran out of energy (trying to heat the brood to 95F) they dropped from the comb and died from the cold.  The energy expenditure of the bees is probably at a maximum in the spring because they are trying to keep the brood at 95F while the night time temps could be dipping in the 20F (25F here in Michigan last night).  If they are too cold or too stubborn to move to new stores under these circumstances, they are going to expire. 

I’m guessing in MA, you probably had some insulation of some sort over your hives in the winter?  My advice would be to keep that insulation on until spring really sets in (Late April, May).  No, it won’t hurt to keep the insulation on in the spring; I keep 2” of insulation around my hives year round.  In the dead of summer, my bees still have lots of foam insulation around them.

[mvanek]

Thanks BlueBee.  That looks like what might have happened...taking insulation off too early.   :'(  I thought it might be bad for them in the hot 80 degree weather, but it sounds like it doesn't hurt your bees at all.  Thanks for the advice.

[mvanek]

Bluebee I think you were right!  But to show you how amazing bees are, even though it got down to ten bees, the hive is starting to build up again.  Shows you never can give up on them!  :)