4.1.1. Seasonal timing of adult worker collection for laboratory experiments
In temperate climates workers can be classified either as short-lived “summer” or long-lived “winter” individuals. Physiological differences, such as in juvenile hormone and vitellogenin levels (Fluri et al., 1977; Crailsheim, 1990; Seehus et al., 2006; Corona et al., 2007; Strand, 2008), are mainly driven by quantity of protein consumption and level of brood rearing by the colony (Maurizio, 1950; Amdam et al. 2004; 2005b). “Summer” individuals can be collected beginning in late spring, after colonies have replaced old “winter” honey bees, and up until late summer, when colonies start to prepare for winter. For specific experiments in which the susceptibility of winter bees is the object of study, one can cage the queen within the broodnest for greater than 21 days so that the queenright colony contains no brood (Maurizio, 1954; Fluri et al. 1982). This mimics the broodless period experienced by honey bees in temperate climates.