Flick arrives during the day, and will stay until 5am if you speak to them. He will buy all bugs for 1.5x bells (compared to Nook's Cranny) - This means each Tarantula will earn you 12,000 bells!
If you give him 3 of the same bug, he will craft you a statue. It arrives by mail, and only one can be made at a time.
Flickr also hosts the Bug-Off event in the summer.