The more important practical question is how much does drone brood  
contribute to varroa mite population increases compared to worker  
brood.  Opening cells of recently capped worker and drone brood to  
quantify relative invasion rates does show a preference for drone  
cells.  However, given the patchiness of brood infestation, even in  
worker brood, and the spatial patchiness of drone cells and their  
ages, it becomes fairly difficult to measure these preference ratios  
with a lot of precision.  Add to these ambiguities the episodic and  
seasonal production of drones, the preference behavior of hygienic  
behavior bees to investigate infested worker brood compared to drone  
brood, and you end up with highly variable scenarios- ranging from  
drone brood likely contributing a very small proportion of the new  
mite populations in colonies with high mite growth on worker brood and  
low amounts of drone brood present to drone brood possibly the main  
source of mite growth in large colonies with a lot of drone brood  
production and mite levels kept low on worker brood through hygienic  
activity.

A challenge for modelers......

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