5.3.1. Use of surrogates
To study the impact of queen pheromone "bouquet" and its components on workers attraction, a surrogate queen is used. The surrogate material needs to be as chemically neutral as possible. Glass slides/micropipettes are commonly used as surrogates. Apply the cues to be tested, for example glandular extracts, and its suspected chemical component(s) or corresponding solvent (control) on the surrogate and allow the solvent to evaporate for about 5 min. The other possibility is to use workers as a substrate to test a chemical. Presenting a secretion on a bee vs. an inanimate object such as a glass slide provides a more natural situation. When using this procedure, apply the treatment slowly on the worker thorax and allow the solvent to evaporate before the bioassay. The disadvantage of this procedure is that worker behaviour and chemical signals may interfere with the assay.