Procedure to obtain worker or drone brood of known age

  1. Find the queen in a colony.
  2. Place an empty comb with worker or drones cells (depending on the needs of the experiment) in a cage with sides made from queen excluder material or purchase a trap cage which encloses the frame and prevents the queen from leaving the comb, but allows workers to move freely in and out to take care of the brood and queen (see Fig. 1 from the BEEBOOK paper on maintaining adult honey bees in vitro under laboratory conditions (Williams et al., 2013)).
  3. Place the queen in the cage for a predetermined time.
    Note: the longer the queen is caged, the larger the range of age of the brood becomes.
  4. Remove the comb and queen from the cage.
  5. Reintroduce the queen into her colony.
  6. Mark on a transparent sheet of acetate the area of comb in which the queen oviposited for future localization (Fig. 5).
    The sheets should be laid over the surface of the comb and the position of cells can be recorded on the sheet using a permanent marker. Be sure to label the sheet and mark it according to its position on the frame (Fig.5) to be able to place it accurately when using it later and thus avoid confusion.
  7. Remove the sheet.
  8. Replace the comb in the colony in middle of the brood area.
    The comb can be placed in the cage again to prevent further ovipositing by the queen (now on the other side of the excluder) in this comb. If done this way, the brood produced while the queen was caged will not be mixed with younger brood produced later.
  9. Collect brood when it reaches the desired age or observe developmental stages at regular intervals, according to the purpose of the experiment.

It is possible to narrow down the age range of the larvae considered for experiments by considering only those that hatched during a chosen period. If larvae are collected for weighing, they should be rinsed in physiological saline to rid them of adhering food.

Fig. 5. Marking the cells freshly oviposited in by a queen on an acetate sheet fixed on the frame. The acetate sheet is fixed to the frame with thumb tacks and its position is marked with lines drawn across the sheet and frame (see left side of the image) for precise repositioning on next use. Photo: V Dietemann.