According to the recent summation below, the behavior of Apis cerana accounts for the difference in mite infestation levels between cerana and mellifera, and no doubt between small cell and large cell bees (ie., African and European). Not the cell size. Obviously, if bees are yanking the mites out of most of the cells, the mites cannot build up very easily. It happens that A. cerana tends to ignore the mites on drone brood, so the mites use that to their advantage. But in A. mellifera some lines tend to be slack on pulling out the mites wherever they are, while others are more diligent. Also, it appears to me that smaller colonies have the brood nest under better control that large ones, as a general thing. Work by Harbo suggests that very large colonies are not optimal for anything except producing large honey crops. For raising brood, small to moderate colonies raise more brood per bee, and may be more hygienic in addition. 

> Tewarson et al.provided the first insights into the life cycle of V. destructor on an A. cerana colony in India. The mite population growth rate in an A. cerana colony is significantly slower than in A. mellifera. Most of the time, the mites infest the drone brood, and it is rare to observe the mites invading worker cells. Thus, the damage to the colony of the mite’s native host is not as severe as we observe in A. mellifera, where mites are found reproducing successfully in worker cells. The defensive behaviours of A. cerana against the mites can explain the low growth rate of the mite population. The worker bees can groom each other to remove mites, a behaviour that is lacking in A. mellifera, and can detect capped cells that are infested with mites, which are later uncapped and the mites removed or both the bee prepupae and the mites are buried together. -- Natapot Warrit and Chariya Lekprayoon, Asian Honeybee Mites 2011

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