There are two bugs to find and use in the game. One is shaped like a fly, and you'll use that one on Alec --
How do I find out more about Alec?
-- and the other is shaped like a dragonfly, and you'll use that one on Bridget.
How do I find and open Bridget's safe?
To listen to the one you want, click on the icon shaped like that bug, then click the triangle at right. You only get one set of conversation from each bug, but you can play it over and over if you like.