What if they keep a bunch of unaltered mosquitoes in captivity while eradicating them in the wild? Then if it does have some unanticipated effect the change ma

What if they keep a bunch of unaltered mosquitoes in captivity while eradicating them in the wild? Then if it does have some unanticipated effect the change may be reversible. (Of course it's possible the re-released mosquitoes will be out-competed by whatever's moved in in their absence, but you've got a better chance than if you didn't keep a backup.)