2.1.3.1. Selection of colonies

A main problem with field trials using free flying honey bee colonies is the large natural variation in size, productivity or behaviour between colonies. In comparative field trials, it is therefore advisable to minimize such variations, and if considerable variation is expected, then increase the number of colonies involved. This can be achieved by using:

  •  Artificial swarms from healthy colonies
  •  Sister queens mated the same way or instrumentally inseminated (see BEEBOOK papers on queen rearing and selection (Büchler et al., 2013) and on instrumental insemination (Cobey et al., 2013))
  •  Adding a controlled degree of infection at the onset of the experiment

Adding a controlled degree of infection at the onset of the experiment can be achieved by adding a known number of bees with a documented degree of infection, either from naturally infected colonies, or from colonies where infections have been propagated for this purpose. Spores can also be sprayed onto combs and bees in sugar solution as is done with American foulbrood spores (see the BEEBOOK paper on American foulbrood (de Graaf et al., 2013)).

Naturally infected colonies can also be used for comparative studies after careful documentation of infection prevalence (see section 2.1.1.).