I use fox squirrel tail but I also use raccoon tail as it is a finer hair. The mix of brown and black hair to me seems more "bug like". I have asked a buddy to harvest a grey squirrel to add to the mix. A coon tail can last a loooong time depending on how many you tie.
1 shot and you are golden for a long time. Coyote might be a good hair too, although I haven't tried it.