larval behavioural process living at the water surface Factors that characterize the water surface: (i)surface tension and (ii)surface film. Aquatic insects which live immediately under the water surface have access to two major resources: (i) They can obtain direct access to the atmosphere for respiration. (ii) They are in the immediate vicinity of food. IDOMAL:0002179 IDOMAL:0002179 Mosquito larvae have the usual internal organs of ion regulation and also they have four external balloon-like anal papillae, which are capable of ion uptake from very dilute solution. They are anatomically adapted for the specific characteristics of the water surface, notably the surface forces in the air-water interface. Mosquitoes (mostly Culidis) form part of the neuston-the assemblage of small to medium-sized organisms that live at the water surface. idomal_namespace