When insects inhale, air is drawn in through the spiracles which are paired openings/pores located externally along the thorax and abdomen of the insect 'insect. These spiracles are lined with hairs that filter the air entering the system to prevent blockage of the respiratory tract and reduction of the surface area available for gas exchange. The spirals also help minimize water loss through the bristles that trap moist air and the valves that help control opening and closing. As insects are terrestrial organisms likely to be subject to desiccation, and therefore to loss of water by evaporation, the closure of their stigmas can allow them to contribute to the conservation of water and ensure that the surface of gas exchange remains humid (so that respiratory gases are dissolved and diffused into the muscle fibers). However, closure of the spiracles may also mean that the flow of oxygen-rich air is limited and the efficiency of gas exchange would decrease, consequently affecting the rate of cellular respiration and energy production needed to meet metabolic demands of an insect. Air then moves from the spiracles to the tracheas/inner tracheal tubes which are supported by rings or strips of chitin (a strong, lightweight material) which help to strengthen and give flexibility to its structure. This ensures that the tracheas remain open instead of being compressed when vigorous body movements are performed and that the gas exchange surface is always sufficiently ventilated with the necessary oxygen to provide the large amounts of energy required for such movements bodily harm, in particular theft during an attempt to escape. predation. As there are many tracheal tubes that branch into tiny tracheoles, the surface area to volume ratio is increased so that maximum oxygen absorption can occur. Tracheoles are tiny tubes that end in a liquid-filled tip in which respiratory gases are soluble to allow diffusion of oxygen from highly oxygenated air.