We called them insects during testing. The reason for the underscores is actually due to a limitation in the current forum software that requires all search terms to be at least 4 letters, making it impossible to search for the word '_bug_' in the forums. At least this way we can find it, even though we have to explain it a lot when people ask about it.

As for catching the insects in the game (and dealing with the camera icon, which can't be disabled), I find that it's easiest to let the insect fly farther down into the greenhouse before attempting a catch.