7.8.1. Starving caged adult workers in the laboratory prior to performing a feeding test
Workers are usually starved to ensure that the entire oral treatment is consumed within a short time. So far, no commonly accepted method for starving individuals prior to oral application of a treatment exists; however, within fields of study there are some consistencies. For example, most experimental laboratory investigations of Nosema starve groups of young workers for two to four hours (e.g. Fries et al., 1992; Malone and Stefanovic, 1999; Higes et al., 2007; Maistrello et al., 2008); starvation for this length is also recommended by Fries et al. (2012) in the BEEBOOK paper describing methods used to study nosema in honey bees. Similarly, up to two hours of starvation is recommended for acute, oral toxicity experiments (OECD, 1998). Amount of food in the honey stomach will no doubt influence length of required starvation time, and resilience to starvation will likely depend on type of collected workers (e.g. age, health, etc.), and if they were starved individually or in a group.
Future studies should investigate effects of both short- and long-term starvation on honey bees, in addition to the influence of honey bee condition, age, and subspecies. Generally, groups of adult workers should be starved for no more than four hours to ensure rapid consumption of a test substance. Workers starved in isolation should be without food for less time – no longer than two hours. Individuals starved for any longer are more likely to be injured or to die. Starved honey bees that do become impaired (e.g. behaviourally) or that exhibit other unusual signs should be discarded from experimental studies. Pre-trials will determine the minimum length of starvation period needed to consistently induce feeding of entire food treatment quickly.