This is literally about mosquitoes.

Mosquitos move calories from big animals, back down the food chain, without killing the big animals. That's important! Mosquito are prey in themselves but mosquito LARVAE are vital food sources for a ton of water animals.

How do you expect to transfer calories from, say, the deer in a forest to the fish in the river, without mosquito as the middle step? How do you expect to transfer calories from rats to bats, without mosquitoes?

Losing mosquitos would fundamentally shift how calories move through the food chain, because they're a parasite that shifts between land, sea, and air. And that's just a foundation, it doesn't cover all the behaviors other animals have specifically to interact with mosquitos.