When it gets cold, a biochemical process replaces some of the water in the mosquito's body with glycerol.
First, it reduces ice formation within the mosquito’s cells, so that water hardens like glass but doesn’t form ice crystals that can then damage the cells.
For the most part fat is stored in the fat cells that compose fatty tissue. Think of a fat cell as a tiny plastic bag filled with a drop of fat. Interestingly, fat cells do not multiply.