That's what's happened here, and I can't help but see it as another case of insurers once again not paying up because they can get away with it.
If they meant "bugs" they should have either have said "bugs", or should have said "insects and other small lifeforms." I'm sure their lawyers could find a way to be more precise, and it seems reasonable to me to require it of them.
But, well, I'm neither a lawyer nor an insurance expert.