The life cycle of the termite begin with a mating flight, wherein established colonies experience winged reproductive males and females leaving, and swarming and then going on to procreate. After fertilization, winged termites land and shed their wings, going on to form new colonies. These insects then become the king or queen termites of their newly-established colonies. The queen and king termites are the center of the termite life cycle and are solely responsible for reproduction. After the fertilized queen lays her eggs, they hatch into pale, white larvae. Over the course of several molts, these larvae grow to assume the role of one of the three termite colony castes: workers, soldiers and reproductive termite, also known as alates. Each caste has a distinctly different physical appearance. Workers are sexually and developmentally immature insects that are responsible for constructing tunnels and chambers as well as feeding and grooming other termite castes. Soldier termites are yellow-brown in color, with dramatically-enlarged heads and mandibles. These are useful in combat but render warriors incapable of feeding themselves. The reproductive alates are black in color and are born with two pairs of wings. Although it is not clear how larvae are relegated to a certain caste, some research has indicated that maturity and the overall needs of the colony may dictate caste assignment. In fact, research has indicated that castes in the termite life cycle are not rigidly set, as termites belonging to one caste may develop into another caste if the colony requires it. Thus, a soldier termite may become a worker or a reproductive termite if the colony experiences a shortage of one or the other. Workers and soldiers live approximately one to two years. Queen termites may survive for up to 50 years under optimal climate conditions.