Protection against toxic levels of iron. Stores iron in a soluble, non-toxic, readily available form. Important for iron homeostasis. Has ferroxidase activity. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation. 4 Fe(2+) + 4 H(+) + O2 = 4 Fe(3+) + 2 H2O Oligomer of 24 subunits. The functional molecule forms a roughly spherical shell with a diameter of 12 nm and contains a central cavity into which the insoluble ferric iron core is deposited (By similarity). Larvae, pupae, and adult females. Detected in midgut. By blood meal, iron and hydrogen peroxide. Belongs to the ferritin family.