Local DNS server access delays
If you have 127.0.0.1 localhost in /etc/hosts you also need to add a ::1 localhost line.

You may find that the delay has something to do with resolving the name 'localhost'. If you use 127.0.0.1 instead, the delay should be reduced to milliseconds.

$ time dig @127.0.0.1  muc.de

;; Query time: 10 msec

real 0m0.029s
user 0m0.007s
sys 0m0.005s

I don't know where the resolution of 'localhost' occurs or why it takes such a long time, but I guess it doesn't really matter...