Within-cavity nest preferences: honey bees favour the entrance rather than the ceiling when initiating their nest

Cavity-nesting animals are limited by the options available in the environment and thus may have to adapt their nest structure to optimize its function. After choosing a cavity, honey bee colonies must decide where to initiate their comb nest within the empty cavity. Within-cavity location preferences remain untested, but previous studies suggest proximity to the ceiling, entrance and east side may be important. To distinguish potential preferences for nest initiation sites, we designed ‘infinity nest’ hive boxes that were extremely elongated (2.4 m), with target features at opposite ends, thus forcing colonies to choose between the entrance, the east side and the ceiling. Not only did colonies show a clear preference for nesting near the entrance (89%; N = 9), but when the entrance was far from the ceiling, colonies modified their nest by building combs from vertical walls. Combs that were attached to walls were more vertically elongated than combs attached to horizontal ceilings, which likely reduces the straining forces from gravity and shows that bees can alter their entire nest structure to accommodate different attachment angles and initiation site preferences. Therefore, honey bees are not constrained to attaching their comb to the cavity's ceiling and instead pursue other important initiation site features, like proximity to the cavity entrance, which may reduce commute time. Given that colonies reuse their nest for multiple worker generations, the decision of where to initiate the nest within a cavity likely has long-term impacts for colony function. This work demonstrates the importance of plasticity in built structures and the extended phenotype.