On with the revision posts for my BBKA Module 6 Honeybee Behaviour exam. I’m trying to work my way through the 21 sections on the syllabus, but the exam date is March 19th, so I’d better start doing more than one of these a week!
So, section 6.3: the queen honeybee’s egg laying behaviour and its relationship to changing circumstances in the hive and external factors relating to climate and season;
and, since it’s related…
6.4: the seasonal variations in the population size of a honeybee colony and an explanation of such variations;
Queens can mate up to 4 weeks after they emerge; after this time it is too late for a queen to mate and she becomes a drone layer. Given good weather, queens generally mate in the first 2 weeks of their adult life.
Once the queen has mated, she soon begins laying eggs, usually within the space of a week after mating. So a good young queen should be mated and laying eggs by 21 days after emerging; but allow an extra week if the weather has been poor.
Her two ovaries are enormous compared to a worker bee’s, with each of the ovaries consisting of 150-180 egg producing ovarioles, compared to 2-12 in a worker ovary. Her spermatheca can hold up to seven million sperm, and it usually takes 2-4 years after mating before all the sperm are used up.
She inspects each cell carefully before backing into it and producing first a sticky substance for the egg to stick to and then the pearly white cylindrical egg, laid at the bottom centre of the cell in a standing position (a laying worker’s abdomen will not reach the bottom of the cell, only the cell sides). Think of her as a bee version of Kim & Aggie from the Channel 4 show ‘How Clean is Your House’, as she is extremely picky about how well the worker bees have cleaned the cells and will not lay into one which has not been cleaned to her satisfaction.
She uses her forelegs to judge the size of the cells built by the worker bees – worker cells are smaller, drone larger. If the cell size is that of a worker, she will release a sperm on top of the egg she lays. If no sperm is attached to the egg, it will develop into a drone. After each egg is laid she moves onto the next cell and repeats the process. It must be an extremely monotonous life after the excitement of flying high in the sky for her triumphant mating flights.
A young, well-mated queen’s laying rate depends on a few factors:
- supply of food, particularly pollen
- seasonal factors, such as temperature
- if the colony is going to swarm soon
Winter – spring
The colony huddles together in a ball shape during winter, keeping the queen warm in the centre. The colony’s population will drop to around 10-15,000 and the queen will be laying very few eggs, because only at the centre of the cluster will the colony be able to keep brood warm enough. In the UK there is likely to be a broodless period during December and possibly longer, during which time the bees can drop the cluster temperature to 21-24°C.
Even within the depths of the cluster, the worker bees can sense the minutes of daily sunlight beginning to increase following the shortest day of the year, the winter solstice on 22nd December. Within a few days of the solstice, they will slowly begin to raise the cluster to a warmer brood-rearing temperature of 34-35°C. This increase in warmth triggers the queen to begin to lay a small number of eggs.
As plants begin to flower in early spring, and workers return laden with the first spring pollen, the queen’s lay rate increases. This increase will only be interrupted by periods of poor weather. A colony trying to raise brood in the winter, before the first flowering plants appear, will need to rely on good supplies of pollen collected during the previous season.
Spring – summer
In the UK the main nectar flow is often over a short three-week period in May-June. As long as enough pollen is being brought in to produce brood food, at the height of the season the queen may lay more than 1,500-3,000 eggs a day, depending upon her race and strain – more than her own body weight in eggs. Apart from short rest periods of 5-10 minutes, she will do this round the clock. Laying such a huge amount of eggs takes a great deal of energy, so a ‘court’ of workers follow her around supplying her with food. The colony should soon have between at least 30,000-60,000 bees, causing a high-risk of swarming, which will reduce the colony population by up to 50% or more if there are after swarms.
Summer – autumn
After peaking in May-June the queen’s lay rate will start to drop off from July onwards, as the colony switches to concentrating on building up stores to survive the coming winter. As less brood is being laid, and workers live for about 40 days, by mid August there is a rapid reduction in worker population. There will be less available forage and the temperature will cool as winter arrives. Over the winter she will either lay very few eggs or stop laying completely.
It is the worker bees who make the decision to swarm, usually as colony population peaks. In the week before swarming they starve the queen to reduce her size and get her light enough to be able to fly. They also act as particularly vicious personal trainers, chasing her around the frames and shaking, pushing and biting her to force her to keep moving. The reduction in food and weight loss causes her egg laying rate to fall before she leaves with the rest of the swarm.
- Celia Davis, 3,6,12 and Counting, BBKA News, April 2013, p9-10.
- Dan Basterfield, Very Simple Queen Rearing, BBKA News, April 2013, p19-20
More revision/Module 6 themed posts:
- 1st Honey bee behaviour revision post: bee jobs
- 2nd Honey bee behaviour revision post: honey bee mating
- 4th Honey bee behaviour revision post: social organisation of the colony
- 5th Honey bee behaviour revision post: bee communication
- 6th Honey bee behaviour revision post: bee foraging
- BBKA exam feedback