Just something to think about.
I have 17 colonies sitting on solid Granite, for 100ft in every direction. I have more SHB at that location than my other which is located on a clay/sand soil.
I too have noticed what seems to be development inside the hives and also primarily in the bottom grooves and any cracks they can find.
Bees that tend to propolize can be a blessing where these pests are concerned. I have made it a part of my regular routine to inspect my hives for any hiding places for the beetles. And seal them myself if the bees haven't.
I have also become a big fan of letting by bees make their own comb in the brood boxes instead of providing foundation. But that's another discussion. So, with that in mind, until I either design my own frames or find another to use. I am also sealing joints and bottom grooves with wax to close up those safe havens for the beetles.
I have not noticed any of my bees that will tolorate the existence of SHB's in their hives, Italian or Carnie. But if they can't get to them, there's nothing they can do about them. So I believe a lot of the management of these pests rest with us. In the quality of construction and maintenance of the hives. And as mentioned above, better planning in the addition of space that the bees will have to maintain.
Great discussion guys!! Hope some more folks will pipe in with their observations.....
"Success is not final, failure is not fatal: it is the courage to continue that counts." Winston Churchill