[denvaar]

Maybe a dumb question, but why release them back? Why separate and raise sterile males when you could kill off both male and female and be done? Is the idea that introducing sterile males back into the population has a compounding effect?

[Bjartr]

Every time a wild female mates with a sterile male, that's one less time they've mated with a viable male. It greatly reduces the number of successful females and therefore the size of the following generation.