Marie Celeste syndrome

In the UK there are an increasing number of reports of what is becoming known as "Marie Celeste syndrome" -- hives being left bereft of bees with no obvious reason for their disappearance.

I know a beekeeper who has lost 40 of 50 colonies over the course of the winter. The reason is as yet unknown. I had one mysterious winter loss.

A number of possible reasons are circulating for the syndrome: simply varroa, pesticide poisoning, a new unknown virus, and queen failure.

The last notion is rather interesting. The scenario, as I understand it, goes something like this: varroa was first found in the UK in 1992, and by 1995 there were huge colony losses in the south of England. Since then, feral colonies have been few and far between -- and destined to die within three or four years. Beekeepers lost many colonies too. So, suddenly the genetic pool diminished. And lately, some beekeepers have been drone-trapping to try to restrict varroa population growth. By reducing drone populations, queen-mating may be impaired.

Lots of people (me included) have been saying that queens aren't what they used to be -- and that mating is poor. Some people have blamed varroa treatments, claiming that they may have affected queen and/or drone fertility.

So, inbreeding is the word. Queens may lay lots of unfertilised eggs and the colony cannot sustain itself, absconding as a response. Spotty brood is a key symptom when the colony is still viable -- the workers remove or eat the unfertilised eggs.

Could that be the cause? More of this again, no doubt. I can't find much on the web about this (but search for Celeste here) , but the March edition of the Beekeepers' Quarterly has some interesting letters.