3.2.2.1. Promoting SHB oviposition behaviour in capped bee brood

The idea of this method is that SHB adults are trapped and allowed to reproduce on a section of brood.

  1. SHBs used in the study can be laboratory-reared, field-collected, all males, all females, age-cohort specific, etc., per the needs of the experiment. They should be at least 1 week old to ensure that they have reached sexual maturity.
  2. Remove a frame of capped brood (~60-90% capped) from a colony.
    The capped brood should not contain any uncapped larvae as these will crawl out of the cells and be macerated by the SHBs in this procedure. Any uncapped larvae in the brood patch should be removed with forceps. It is best to use a section of brood that does not contain any honey stores. Furthermore, the selected brood should be > 6 d from enclosing (determined by uncapping and examining select brood cells in the test area, see the section on obtaining workers and brood of know age in the BEEBOOK paper on miscellaneous methods, Human et al., 2013) so that no bees will emerge during the test period.
  3. Prepare a sheet-metal, push-in cage (10 x 10 x 2.5 cm cage, L x W x H).
    The face of the cage should be screen mesh to allow for ventilation. The screen mesh should be too small for SHBs or bees to traverse.
  4. Trap the required number of SHBs in small vials.
  5. Place the vials on ice 4-5 minutes.
  6. Once anesthetized, dump the beetles onto the brood section.
    Trap the beetles on the section by pushing the cage onto the section and into the wax to the comb midrib.
  7. Return the frame containing the beetles caged on a section of brood to the centre of the bee cluster in the colony from which the brood was removed.
  8. Allow SHBs to mate and the females to oviposit for 24 hours.
    Though the length of time for this can vary, the beetles may not oviposit in the brood cells sufficiently if allowed less time. In contrast, they decimate the brood section beyond use if allowed access longer than 24 hours. This is especially true if >20 adult SHBs are added to the comb section.
  9. After the oviposition period concludes, remove the combs from the colony
  10. Collect the cages and beetles.

Note: It is important to know that some adult SHBs may exit the cage during the oviposition period unless the cage is pushed firmly into the comb. Likewise, SHBs already present in the colony at the time of the study can migrate into the cage. These situations usually only present a problem if one is trying to investigate the oviposition behaviour of an exact number of beetles.