Preserving valuable queens

The queen has a lifespan of 4–5 years. This may seem long. However, it takes 1–2 years to identify a valuable queen and select her for (re)production. To preserve this queen for as long as possible, her egg laying must be managed carefully, as it depends on the number of spermatozoa present in her spermatheca. Various techniques make it possible to modulate egg laying: colony size, the surface of empty cells, the population of young bees, protein resources …

Factors influencing queen lifespan

The lifespan of the queen, which can reach 4 to 5 years, is closely linked to the number of spermatozoa contained in the queen’s spermatheca. This depends both on the quality of mating and on the queen’s egg-laying rate (Baer, 2016). Mating can be managed in order to optimize filling of the spermatheca: natural mating in an environment rich in drones during a suitable weather window, instrumental insemination with an appropriate volume of semen, etc. These parameters are relatively easy to control when the season allows.

The egg-laying rate, on the other hand, can be influenced by the beekeeper by acting on:

• The overall size of the colony (the number of worker bees accompanying the queen): The larger the colony, the larger the brood area tends to be, and the more the queen is driven toward a high egg-laying rate (and thus a greater use of the contents of her spermatheca) (Harbo, 1986). A queen introduced into a very populous colony is therefore not under optimal conditions for use over several years. Conversely, a queen placed in too small a population may not overwinter under good conditions, which can also affect her survival.
• The surface available for egg laying: The queen’s egg laying is facilitated when many empty cells are available to be filled with eggs (for example, recently emerged brood) (Harbo, 1988). Conversely, in situations of brood blocking (for example during a strong nectar flow), the queen has less space available and tends to restrict her egg laying.
• The number of young bees in the colony: The queen and the larvae are supplied with royal jelly by nurse bees (young bees). A colony with many nurses can support a larger amount of brood than a colony composed mainly of foragers (Schmickl, 2004); moreover, in the former case the queen is fed more efficiently and herself shows a more intense egg-laying behavior (Farrar, 1931).
• The available resources: A queen in a colony with abundant protein (and carbohydrate) resources available will show a higher egg-laying rate during periods of resource abundance (in the absence of brood blocking), due to better nutrition (Farrar, 1931; Keller, 2005; Imdorf, 2008).

Which levers of action for beekeepers?

Few methods are described in the literature to reduce the egg-laying effort of queens. Nevertheless, in view of the factors affecting it, the beekeeper can influence the queen’s egg-laying behavior by acting on several parameters:

• Limiting hive size: favoring intermediate formats (nucleus hives, Warré hive elements, etc.) over larger formats (production Dadant hives), which promote a high egg-laying rate, or very small formats (Miniplus), which are more difficult to overwinter;
• Limiting the surface available for egg laying: providing the queen with a limited number of frames suitable for egg laying, corresponding to her maintenance in a small colony (adding/removing empty frames);
• Adjusting colony size and/or the nurse-to-forager ratio to limit the number of nurse bees (removal of emerging brood, taking a package of bees, etc.);
• Whenever possible, modulating food inputs by placing the colony in an environment that allows a regular but not excessive supply of pollen and nectar resources.

The beekeeper will also ensure, through management practices with respect to varroa and by choosing apiary locations relative to risk areas (treated crops, etc.), that the effects of pathogens or phytosanitary risks are minimized. In this context, it may be advisable to distribute valuable queens across different apiaries in order to maintain genetic resources even in the event of a location-specific problem.

Use

Valuable queens can thus be more easily preserved over several years. The beekeeper will take care to adjust the bee population (for example, by strengthening colonies in autumn or removing bees in spring). A drawn comb is introduced into the brood area 4 to 5 days before the planned grafting date, in order to have larvae of a suitable size available (the queen may optionally be caged on this frame) (Human, 2013).

A practical example

Gilles Fert (Fert, 2009) recommends the use of the following technique to preserve valuable queens: he suggests using a production hive set up in warm way (entrance parallel to the frames), with a queen excluder allowing the queen to be confined to three frames in the area farthest from the entrance. Foragers tend to store honey and pollen in the frames close to the entrance, thereby limiting the risk of excessive brood blocking on the frames where the queen is located. During the season, the queen thus has around her a balanced population of moderate size. For overwintering, the colony is carefully fed (in particular with pollen if necessary) and can be reinforced with one or two frames of emerging brood from other colonies.

► Article: blog-itsap.fr/economiser-reines-de-valeur/