Many insects have been known for decades to hold their breath when resting, but the reasons have not been well understood. A new study on cockroaches suggests the insects reduce their breathing to conserve moisture.
Cockroaches can hold their breath for up to seven minutes. Their respiratory system is highly efficient but there are no lungs. Instead, the insects draw in air through external valves called spiracles and transport the air directly to the cells via tubes called trachea. To stop breathing, they simply close the spiracles.
The new study, reported in the Journal of Experimental Biology tested the major hypotheses put forward to explain the practice of holding the breath for long periods. One hypothesis is that the insects are trying to build up the carbon dioxide produced during respiration, which makes it easier to expel from the body. Another idea is that they stop breathing to protect themselves from high oxygen concentrations (which can be toxic). The third hypothesis is that the practice aims to regulate water loss.
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Source: www.physorg.com