You do realise that there is more than one species of mosquito? The human pathogen spreading species (less than 1% of all mosquito species) play no important role in any natural ecosystem.
Well, you see, what I did is search for the specific mosquito from the quoted text and found a link to a species of spider who's primary food source is the very same mosquito being discussed.
So either the scientist isn't very good at the google or just doesn't like "vampire spiders" and is lying about there being no predators for this mosquito. Whichever way you look at it this is the person you're trusting to release genetically modified organisms into the wild.
I was able to find one reference to this spider in the context of mosquito elimination:
Regarding ecological issues surrounding the release of sterile TMs, of particular importance is that a reduction in the number of Anopheles is unlikely to have a negative impact on local food chains. According to (Pennetier et al. 2010) there are no birds, fish or other insects that feed exclusively on Anopheles mosquitoes, the only known exception being Evarcha culicivora, an East African jumping spider that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey.
Even Evarcha culicivora will be fine as it is not just living off human disease carrying Anopheles species. Even if it was going to be wiped out I think that it is a minor price to pay to rid the world of Malaria.
So either the scientist isn't very good at the google or just doesn't like "vampire spiders" and is lying about there being no predators for this mosquito. Whichever way you look at it this is the person you're trusting to release genetically modified organisms into the wild.