Survival Rate of New Queens

I’m going to be dipping into some research by the Rural Industries Research and Development Corporation in Australia in 2003. You can get the research paper here. It’s by Rhodes and Somerville and has some clues that should help with introducing queens.

Some of the things they studied were:

• Survival of introduced queens depending on their age at the time of introduction (how many survived 14 days after introduction and 15 weeks after introduction)
• Performance of queens in the field depending on queen age at introduction
• Amount of sperm in the queens’ spermathecas
• Presence of specific queen pheromones

Failed introductions

Many beekeepers are familiar with failed queen introductions. For beginners, this can often be because there was another queen, probably a virgin, in the colony when they added the new queen. That doesn’t end well for the introduced queen. However, nobody has 100% success with queen introduction – even seasoned commercial beekeepers. Perhaps this study sheds some light on why things don’t always work out.

Queen age when caught

The age of the queen in days is the number of days since emergence from the queen cell. Obviously, at seven days, some queens are not even mated yet. Many queen producers catch their queens at around fourteen days. They want to cycle through as many rounds of queens as possible and don’t want to risk bees absconding due to lack of space. Over three years, the results for queen survival fourteen days after introduction were as follows:

As you can see, queens caught at less than 21 days did not do very well compared to those caught at ages 21 days and over. 35 days was best. How many of us wait that long before catching queens? After all of the work that goes into raising queens and getting them mated, it would be good if they lasted longer than a couple of weeks in their new homes. They did some work looking on banked queens, but I’ve excluded that.

If we now look at the same thing, but after the queens have had fifteen weeks in the hives, this is what we find:

As expected, giving queens another 13 weeks in the hive has led to fewer surviving. All sorts of things can happen in a beehive, so, unsurprisingly, some more of them snuffed it. However, comparing survival at 15 weeks to the queen’s age when caught, we can see that the older queens do better. To me, the acceptable cut off point has now risen to 28 days. Based on these findings, I will aim to leave queens in their mating nucs until at least 28 days after they emerged.

Lots of sperm

What about the amount of sperm in the spermatheca? Poorly mated queens become drone layers, which is not desirable for beekeepers. The chart shows a wide range of sperm counts but that, once again, queens caught when older had more sperm on average. I would have thought that anything over a million sperm in the spermatheca would be OK – probably enough to last three years. More is better, of course. These numbers add more support to the notion that 28 days old is the sweet spot for taking queens from their mating boxes.

Off with her head

The researchers beheaded the queens and analysed the pheromones inside. Pheromones from the head and mandibular glands are likely to be critical factors in worker bees finding their new queen acceptable. Presumably, they want their queen to smell like a queen: healthy, with plenty of sperm and wafting its scent to all corners of the hive. I have lifted the tables straight from the paper. Once again, the sweet spot for the age of caught queens is 21 to 28 days from emergence.

David Kemp on Brother Adam

It’s not all about the age of the queen, though. Clearly, you want the receiver hive to be hopelessly queenless to maximise your chance of success. Ideally, you also want your new queen to be in tip-top shape and laying eggs. This is from my interview with David Kemp, who was Brother adam’s assistant for many years:

Steve: OK, so introducing queens, I think I read somewhere that he would just put new queens straight into the colony and they would be accepted because they were laying queens, is that right?

David: He’d go up to Dartmoor with cages. If it was Spring, there would be a picnic basket with a copper water bottle underneath and blankets [with warm water in the copper bottle]. He’d take the queen out of the mating hive, clip one-third of one wing – they weren’t marked in those days because we all had decent eyesight – and pop her in the cage. You put about four attendant workers with her, maybe half a dozen if it was very cold, plug the cage up (he had his own special cage), plug it up with candy of his own special mixture [laughs] and put them into an envelope with a number on. They would then go into this warming basket.

When we got the required number, we were off to the out apiary. He would go up to the hive, put the roof cater cornered [diagonally] on the ones that needed re-queening, leave the queen in her cage on the crown board. Our job was to find the queen, and if it was still good, it would go to Dr Harding or Rothamsted, and if it was no good, it was killed. But you see, we often took the old queen back to the mating station to go back into the nucs, to keep them ticking over. 

Steve: So it was introduced in a cage, it wasn’t just running the queen in?

David: Yeah. It was a laying queen, only in the cage for a couple of hours, put straight in so the bees could eat the candy and release her. Within a week or less, we’d go round checking to see if the queen was on the comb then quickly close up. You got a few that were balled or went missing.

Adam did not wait for the receiver hive to be hopelessly queenless back in the day. However, the fact that he was introducing a healthy laying queen straight away seems to have been the main reason it worked in most cases. She had only been in the cage for a couple of hours – another advantage to raising your own queens. Bought queens have been caged for a few days, and they are not the same thing at all.