Dead Brood of Apis mellifera Is Removed More Effectively from Small-Cell Combs Than from Standard-Cell Combs.

Simple Summary: Honeybee workers are able to detect dead or infected brood in comb cells and remove it outside the nest before the infection spreads onto the colony. Such a phenomena is called an hygienic behaviour. Colonies with efficient hygienic behaviour are more resistant to diseases. Bee comb cells may vary in width. In Europe, standard-cell combs (cell width approx. 5.50 mm) and small-cell combs (cell width approx. 4.90 mm) are used. Typically, colonies are kept only on standard- or small-cell combs. We assessed the dead brood removal efficiency in colonies kept on both comb types. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The removal from small-cell combs was significantly more efficient than in the case of the standard-cell combs, which indicates that bees find dead brood in small-cell combs faster or devoted more attention to the removal. Better understanding of the effect of the simultaneous keeping of colonies on standard- and small-cell combs on the efficiency of hygienic behaviour may contribute to enhancement of the resistance of bee colonies to diseases. The efficiency of the hygienic behaviour in bee colonies towards dead brood was assessed in small-cell combs (SMCombs) and in standard-cell combs (STCombs). Each colony had both types of combs in the nest on a permanent basis. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The number of killed pupae removed within 24 h was the measure of the hygienic behaviour efficiency. Regardless of the year, the brood in the SMCombs was uncapped and removed significantly more efficient (p ≤ 0.01) than in the STCombs (number of non-uncapped cells: in 2020 SMCombs = 3.79, STCombs = 11.62; in 2021 SMCombs = 2.34, STCombs = 5.28 and completely removed cells: in 2020 SMCombs = 87.46, STCombs = 80.04; in 2021 SMCombs = 96.75, STCombs = 92.66). In colonies kept simultaneously on standard- and small-cell combs, the width of the comb cells has a significant effect on the efficiency of removal of dead brood, which is removed more efficient from small-cell combs than from standard-cell combs. [ABSTRACT FROM AUTHOR]