Mosquitos are the only flying soldier unit, and also have the weakest stats in the game. Mosquitos are one of only 3 who have 1 in melee growth, shared with the firefly and cicada, and one of only 2 with 1 in gun growth, shared with only the ladybug.
Mosquitos start with only 10 more attack power than ants, but are then beat out because of their +10 weapon contrasting the +20 ant fang. It is clear that mosquitos are simply supposed to be annoying units who fly, with very low stats. Oddly enough, mosquitos don't stop appearing in story chapters, but there aren't any mosquitos in the endgame Badlands.
If a drone has any stat less than the mosquito, it is made very clear that that drone is useless in that category. While it is impossible for a unit to have anywhere near lower gun accuracy, or a lower cannon accuracy, the cicada and firefly have two thirds of its melee power. The strider, butterfly, dragonfly, ladybug, and moth all have near the same melee value. Ironically, because of its starting melee power, no unit beats it at level 1 than the rhino beetle, bee, and pillbug. The spider and stag beetle have the same starting melee power, while the mantis has lower. Although the ladybug has higher starting gun power, the ladybug still has at least 30 less gun accuracy than every other unit. Every unit but cannon versatile drones have the same cannon accuracy as the mosquito. Not even the pillbug has less speed, but the butterfly, firefly, mantis, dragonfly, ladybug, and spider have only 5 more defense than the mosquito. The firefly, dragonfly, and ladybug all have less HP, with the butterfly and locust not much higher. The moth is the only flying unit with as little MOV.