08/24/2026
One of the coolest things you’ll see doing resistance assays is also one of the easiest things to overinterpret.
That white f***l patch on the pupa abdomen is evidence that a Varroa mite entered the cell but failed to reproduce. In a brood assay, that mite gets scored as non-reproductive.
Why did she fail? That’s the harder question. We don’t necessarily know.
And finding one of these does not mean you have a resistant colony. Every colony has some degree of mite infertility, which is exactly why resistance assays require looking at enough infested cells to determine whether there’s actually a pattern.