Old honey bee brood combs are more infested by the mite Varroa destructor than are new brood combs

Varroa destructor preferentially invades larger honey bee brood cells. Consequently, it was expected that brood in old combs with reduced-size cells would be less infested than the brood in new comb cells. An old brood comb was placed in each of eight Africanized honey bee colonies, along with a new, naturally constructed comb (without comb foundation). The mean percentage of brood cells infested with V. destructor was significantly higher in the old combs (22.6%), than in the new combs (9.75%), even though the inside width of the cells was significantly smaller in the old (4.58 mm) than in the new combs (4.85 mm). Within the range where there was an overlap in the width of brood cells between old and new combs, which was from 4.5 to 4.9 mm, the old comb cells were over four times more frequently infested with mites than were the new comb cells. Some factor other than cell size makes old brood comb cells much more attractive to V. destructor than newly constructed brood comb.