I have found that I cannot define a permissions so that Community Members can delete only their own comments on Blogs and Wikis.
I defined the following permission for the Community Member role for blogs:
Community Member > Blogs > Update Discussion
Community Member > Blogs > Delete Discussion
However, this allows the community member to delete/edit the comments of all other community members. Is there a permission I can define to only give community members the ability to edit/delete their own comments?