I installed Screened Beetle trap bottom boards on all my hives about a month ago. I have noticed that some hives hardly have any SHB (1 or 2) but some have quiet a few when I remove the top cover. The only difference in the hives is that the ones with low numbers of SHB seem to be the hives with the entrance reducers. Whats funny is the large strong hives are the ones I removed the ER's from because of congestion and their the ones with the most beetles. The small weeker hives with ER's have hardly any beetles. I guess the full opening is harder for the bees to keep them out? I installed ER's on all hives last night. We'll see if numbers go down. Am I thinking right on this? Entrance reducers may help with SHB's.