Last week’s blog explored one option for rearing queens known as the Cloake Board Method. An important step in the queen rearing process is grafting the larvae. There are multiple techniques and tools which can be utilized to graft queens, and this week’s blog will explore those options and hopefully provide guidance to beekeepers who are new to queen rearing.
Queen Grafting Techniques and Tools
Beekeepers who intend to produce queens on a larger scale typically do so by grafting. Grafting is the process of transferring a larva from a brood cell into a plastic or wax queen cell cup1. This process is also known as the Doolittle method. Grafting takes an abundance of practice, and the small details of the process cannot be overlooked. To be successful at grafting a beekeeper must have patience, a steady hand and excellent vision.
The first step in the grafting process is to select a grafting frame from the breeder colony1. The chosen breeder colony should have the desired traits the beekeeper wants within their operation, such as: a good laying queen, strong colony build-up, and non-aggressive behavior. The desired traits of a breeder colony are entirely dependent on the beekeeper’s needs and preference. In many larger scale queen producing operations their priority is to keep a high amount of genetic diversity by grafting from numerous breeder colonies all with different genetics.
Furthermore, when selecting the grafting frame from the breeder colony there are specific things to look for. The most important thing to find on a grafting frame is an abundance of larvae that are between 12 and 24 hours old1. These larvae will be very small with a slight comma-shaped curvature, while older larvae are larger with a more defined C-shape1. The age of the larvae affects the acceptance rate of queen cells1. A study by Rehman et al. found that the younger the larvae are grafted the higher the acceptance rate of queen cells in colonies. Larvae that were grafted between 12-24 hours had an acceptance rate of 76.7%, whereas those grafted between 24-48 hours had an acceptance rate of 55.7% and if grafted between 48-72 hours the acceptance rate dropped to 20.0%.
There are additional risks to grafting older larvae as well. First, queens produced from older larvae do not perform as well. Second, if larvae vary in age, there is a risk of the older larvae developing first and emerging prior to harvesting cells. The earliest queens to emerge are likely to kill other developing cells, which may be a serious loss of time, money and resources.
Once the grafting frame has been taken out of the breeder colony it is essential to start grafting right away. This is because larvae are vulnerable to chilling, desiccation and starvation outside of the hive1. The use of a damp towel over the grafting frame can help keep the humidity high enough for the larvae short term. Most often grafting is done in a sheltered warm area. It is typically easiest to place the grafting frame on an incline and use a headlamp to find the ideal larvae on the frame. Therefore, it is important to select a frame with lots of young larvae to minimize the amount of time spent searching for the correct larvae.
There are a variety of grafting tools to choose from. When new to grafting, it is recommended to try a variety of tools to determine a personal preference. Two of the more popular options for grafting tools are the Chinese tool and the German tool. The Chinese grafting tool has a pliable plastic tip which slides under the larva and royal jelly, and it is a good option because it provides a sufficient amount of royal jelly into the cell cup1. The German tool is made of stainless steel with a fine tip end, which provides good precision when picking up and setting down the larva.
To graft, place the grafting tool underneath the larva and gently lift it outside of the cell. It is best practice to graft from behind the curvature of the larva and aim to scope a small amount of royal jelly too. Always place the larva down in the exact same position it was retrieved in. Changing the position of the larva could result in the larva drowning in royal jelly. Larvae are placed into queen cell cups and the cups are placed into grafting bars with fit into the grafting frame. When transporting the newly grafted frame cells should face upwards and can be covered with a damp cloth to avoid desiccation.
There is a benefit to priming the queen cell cups with royal jelly prior to placing any larvae inside of them1. Priming with royal jelly prevents desiccation and provides a small amount of nutrition to the larvae1. However, as mentioned, larvae can drown in royal jelly so be careful of their placement and use the royal jelly sparingly. The study by Rehman et al. found that priming cells with royal jelly resulted in a queen cell acceptance rate of 78.8%, whereas those not primed with royal jelly (dry grafting) had an acceptance rate of 37.8%.
Overall, grafting allows beekeepers to make large numbers of queens. The process of rearing queens through grafting requires an abundance of practice to be successful and is a rewarding skill to learn.
Connecting with ATTTA Specialists
If you’d like to connect with ATTTA specialists or learn more about our program, you can:
visit our website at https://www.perennia.ca/portfolio-items/honey-bees/
Email abyers@perennia.ca
References
- Rehman, N.U., Anjum, S.I., Qureshi, N.A., Khan, M.H., Albasher, G., Kaleem, M. and Kamal, A., 2024. The effect of larval age, and wet and dry grafting, on the rearing of queen bees using the Doolittle grafting method. Entomological Research, 54(1), p.e12700.