So, I was curious what kind of worms we have in our blackberries when they get extra ripe. I found this article. I'm not sure if they're the same worms, but I wouldn't be surprised. I found one of the blackberry worms (or so it appeared) in a wonderberry, too.
The article talks about a fruit fly that deposits eggs in berries (especially blackberries) and how it recently colonized all of North America. The worms are said to be edible, but I don't know of any scientific studies supporting it. I'm sure I've eaten them unknowingly and survived, though.
EDIT: After looking at the pictures of the worms and photos, I don't think these are the same things I've seen in our blackberries. The ones in our berries seemed to have been larger, whiter, and were always wet with the berry juice (I never saw them on the outside).