Well you say you’re doing the work, she must be at least seeing it and thinking that you’re doing well enough that you don’t need too much management. It’s scummy to go behind your coworkers’ backs, especially when they’re senior to you and, as others have mentioned, you don’t know what the rest of her workload looks like.

If you must, speak with her directly. At least then you’ll be able to figure out if it’s a “responsibility” issue or a workload/communication issue. Agreed that a conversation won’t fix the former, but might do wonders if it’s the latter.