I'm not sure who told you malathion would only kill the Medfly but it can be highly toxic to both bees and flies (includes mosquitoes) especially when aerially applied. I worked in the CA Medfly program in the 1980s.
BTW, what is a Godzilla bug? I found one internet reference to the name as a praying mantis.
Oh, I meant the only flying bugs that survived are the tough, ugly waspy Godzilla-like bugs that scare me, and not the lacey, pretty harmless butterflies and such.