Colin Gasking Butler (1913–2016)
2.9 Queen introduction cage
Colin Butler was one of the world’s most distinguished entomologists. The research for which he was best known was carried out at Rothamsted Experimental Station (now Rothamsted Research) in Harpenden in the 1950s at a time when the mechanisms of social cohesion in honey bee colonies were not well understood. He is credited with the discovery of the pheromone known as queen substance. This scientific breakthrough transformed our understanding of the social behaviour of bees.
When a queen is removed from a colony, the behaviour of workers changes from a state of organised activity to one of restlessness. After a few hours, they will have modified one or more cells containing female larvae into emergency queen cells.
Beekeepers assumed that the queen must emit some sort of odour by which workers were aware of her presence. When this is absent, they begin rearing new queens. To test this theory, Butler placed a queen in a wire gauze cage and located it in the middle of her hive. Workers could not touch her. He observed that the workers’ behaviour changed to that when the colony was queenless and they began rearing new queens.
He concluded that the queen was producing some physical or chemical signals that kept the colony stable and these were being transmitted, not through smell, but through physical contact with her attendant workers. No one had reported seeing any physical signals, so the latter theory, that these were chemical signals from the queen, seemed the more plausible.
Queen Substance
Butler then compared the behaviour of workers that had left the queen after licking the special wax which covers her body, with those of other workers which had examined her body with their antennae, but had not licked her. Each of the bees that had licked her body offered regurgitated food to other colony members within the first five minutes of licking her, while the other bees did not. In other experiments he observed that workers became just as attracted to cotton wool rubbed on a queen as to the queen herself. It has been suggested that Ronald Ribbands, who also worked at Rothamsted, may have given Butler the idea about queen substance.
Butler concluded that of all the factors that keep members of a colony of bees together, ‘the strong desire for queen substance is probably the most important’. He went on to show that queen substance is produced in the queen’s mandibular glands, and in 1959, in collaboration with Robert Kenneth Callow (1901–1983), queen substance was identified as 9-oxodec-trans-2-enoic acid. They also showed that this acted as the sex-attractant for drones when deployed at about ten metres above the ground, the height at which queens fly on their mating flight. This was the first demonstration of a sex-attractant pheromone.
Queen Introduction Cage
Using this knowledge, Butler devised a queen-introduction cage which would protect a queen introduced into a new colony until the resident bees had been able to receive queen substance from her and distribute it around the colony, making them recognise her as their new queen.
The Butler queen cage is made of woven-wire mesh of 22 swg (standard wire gauge) with holes of 1/8 inch square (3 mm2) through which the bees can lick and feed the queen. The wire is bent into a square cage approximately 3/4” x 1/2” (19 mm x 13 mm) cross-section and 31/2” (89 mm) long. One end is plugged with wood and the other left open. A queen is inserted into the open end of the cage which is then covered with newspaper or tissue paper, held in place with an elastic band. This needs to cover sufficient of the cage length to give the queen somewhere to hide as worker bees can bite at her legs through the mesh. There are several variations of the cage and today plastic versions are also available.
Using the Cage
The simplest and most popular introduction method is to place the cage securely, paper-end down, between two adjacent frames of brood. Alternatively, the open end can be blocked with either fondant or stiff queen-cage candy. The bees in the colony will eventually chew through the paper or eat the candy and release the queen.
References
Anon (2019). Colin Butler, entomologist – obituary. The Daily Telegraph, 8 November.
Brown, Ron (1994). Great Masters of Beekeeping. Bee Books New and Old. ISBN: 978-0-905652-31-3.
Morse, Roger and Hooper, Ted (1985). The Illustrated Encyclopaedia of Beekeeping. EP Dutton Inc, New York. ISBN: 978-0-5252-4243-7.
Plastic Butler cage (courtesy of E H Thorne)
Colin Butler (The Daily Telegraph)
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