Throw a few workbenches on top of the walls or some raised platforms. Dollars to donuts it is fulings. Lox can generally manage to kill deathsquitos, but if you have a fuling spawn, one where they throw down a campfire, that can really be dangerous to lox. Usually if there is a fuling campfire spawn, there is a spear & fire (torch) wielding fuling, and you know how weak lox are to fire.