The antennae of male insects in many species are very feathery. The females of these species release distinctive scents, called pheromones. The male's fuzzy, extrasensitive antennae enables him to locate a female, even when she is far away. Although mosquito larvae and pupa develop in water, they must breathe air in order to survive. Mosquito larvae have a tube, which varies in length in different species that they project through the water surface for breathing.
Breathing is accomplished through a pair of holes at the tip of the tube.
The breathing holes are protected by a rosette of hairs that spreads out on the surface helping to stabilize the larvae in this position. When disturbed, the mosquito larvae 'wriggle' off towards the bottom of the water, sometimes staying submerged for ten minutes or longer. It looks like oil because it is oil. Mosquito larvae need to breath air to survive. We often use diesel oil mixed with an surfactant to control mosquito larvae.