Subscribe flag to auto-subscribe authors
For the Answers module (you know the dril: I'm a co-maintainer ...) to function, you must have the Rules module enabled also.

Therefor, have a look at this rule (in Rules export format, use the Rules UI to import it in your own site):

{ "rules_subscribe_question_author_automatically" : {
    "LABEL" : "Subscribe question author automatically",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "flag", "rules" ],
    "ON" : { "node_insert--answers_question" : { "bundle" : "answers_question" } },
    "DO" : [
      { "flag_flagnode" : {
          "flag" : "subscribe_answers_notifications",
          "node" : [ "node" ],
          "flagging_user" : [ "site:current-user" ],
          "permission_check" : "1"
        }
      },
      { "drupal_message" : { "message" : "You\u0027ve been subscribed to your own post automatically (use the unsubscribe link if that\u0027s not what you want)." } }
    ]
  }
}


For those who are not an expert in Rules-ese, this is what the above rule will do:


Rules Event: after saving a new node of type "Question".
Rules Actions:


flag that node by the user who created it, by the flag with machine name subscribe_answers_notifications (which by accident is exactly also what happens if a user manually clicks the "subscribe" link (below the question).
Show an informational message like "You've been subscribed to your own post automatically (use the unsubscribe link if that's not what you want)."



I think this Answers (oeps: answers) the question ... which was "... authors are automatically subscribed to those types of nodes that they author ..."

Notes:


in case some author does not want to be subscribed to a question author by that author, it is still possible to use the unsubscribe link  (typically bottom right below the question) after they created their question (node).
the above rule only applies to nodes of type "Question", though with a minor improvement you could as well make it work for type "Answer".