While most of them are birds, there are a couple of insects available:
If you really never want to miss a call, though, I’d go with the Barn Owl.
For more advanced nerds, here’s instructions on how to convert any MP3 file into a ringtone. (Audacity has detailed additional instructions here.) That makes any insect recordings online potential phone bling!
In other news:
Circus of the Spineless is BACK! Check out the latest at the Other 95%.