A new study on cell size appeared in Apidologie, Volume 33

He studied varroa reproduction in Apis mellifera scutellata. His conclusions:

>Although reproduction of Varroa sp. is affected by the space between the developing bee and cell wall, reducing cell sizes as a mite control method will probably fail to be effective since the bees are likely to respond by rearing correspondingly smaller bees.

from:
Reproduction of Varroa destructor in South African honey bees:
does cell space influence Varroa male survivorship?
by Stephen J. MARTIN &  Per KRYGER