As it eats the nutritious gall tissue, it passes through two larval stages. Fall The full-grown galls of fall are about 1 inch in diameter. Inside, the fat larva is now full-sized too, and it is forming a tunnel that stops just short of going all the way outside. It will use this tunnel in spring to escape. In the meantime, it will overwinter in the gall.
Winter Triggered by cold weather, the larva makes a type of antifreeze call glycerol.
By keeping the liquid inside the cells from freezing, the glycerol protects the larva's delicate cell membranes from being destroyed by ice crystals. After many months of being frozen and inactive, the larva finally turns into a pupa as the warm spring weather arrives. Two weeks later the adult fly emerges, scoots through the tunnel, and bursts through the thin gall wall. Then the cycle begins again. The center of a busy community Plants are at the first level of energy users.