> But if it doesn't kill the mosquitos, or damage them, they will eventually learn that it's unharmful, and it will no longer be effective. If a repellent stim

> But if it doesn't kill the mosquitos, or damage them, they will eventually learn that it's unharmful, and it will no longer be effective. If a repellent stimulus no longer harms them, that doesn't automatically mean there's any strong advantage to not being repelled anymore. (And I would avoid uses phrases like "learn" to describe this behavior. A population of mosquitoes may evolve to no longer be repelled by chicken smells, but that doesn't mean they're remotely aware of it.)