Not trying to disagree with anyone, but from my experience as a businessman selling and installing cellulose insulation, the boric acid keeps the insects out as even before ingestion it is abrasive and draws out moisture. After a day of working without gloves my hands got so dry they would crack and bleed. Never, ever did I find bugs of any type in attics with cellulose insulation. Why is it in the insulation? Actually for fire retardant characteristics....for what that is worth.
I do agree it is not good for bees, but I think more in contact with it over eating it, as bugs just don't like it, not even spiders. They stay away from it....Smell????