Along with shade versus full sun, I have noticed the colonies in full sun that have more beetles than the others are usually the ones with the highest varroa mite counts.
I have noticed, in the same beeyard, the hives placed where there is alot more shade are the ones that have much higher varroa counts later in the season. At one yard, this has been a consistent observation for 3 years in a row. No beetle issues here so cannot correlate the two together.
Just an FYI observation from here.
Mr HP I have noticed the same thing with SHB here in my area. It seems that they do better against a hive in the shady areas. I had heard this and trusted that the experienced folks were accurate in their reports. So me being me, I had to experiment with both eyes open so to speak, found the same results to be true as others who report of such with SHB. So; it is apparent that the sun is the best place for bees in conjunction concerning both of these pesky parasites. Thank you for your report of varroa backed with your years of experience to verify. Much appreciated. 👍🏻