Levels (genome copies per bee) of DWV, BQCV, and IAPV in local and non-local colonies at two different times (T1 and T2). T1: fifty-bee samples were collected from 20 local and 20 non-local brood chambers 12 days after requeening. T2: fifty-bee samples were collected from 20 local and 20 non-local brood chambers 40 days after requeening. From T1 to T2, IAPV loads increased in non-local colonies and were lower in local colonies at T2;


p 0.001