Big Brains Steal Insects’ Breath Away (From The NY Times)
There is a type of cockroach that can go without breathing for seven minutes at a time, and a moth pupa that can go several hours without breathing. Now a new study in The American Naturalist reports that there is a commonality among insects displaying this behavior: they have large, complex brain structures.
The behavior, known as discontinuous gas exchange, is seen only in certain insects, and only when they are in a resting state.
“If you’ve got a big brain, it’s costly to run,” said Philip Matthews, a physiologist at the University of Queensland in Australia and the study’s lead author. “If you go into a sleeplike state, you can save energy.”
When in this state, the insect will stop breathing for a long period of time, followed by a series of short breaths, and then one long breath.
To conduct the study, Dr. Matthews and a colleague, Craig White, studied the brains of several species of insects that display this behavior.
They found that when the insects’ brains were removed, they displayed discontinuous breathing patterns.
“They have a nerve cord comprised of ganglia, which are kind of like mini-brains,” said Dr. Matthews. “We think that when the insect is active, the brain is sending a constant message to breathe, but when it’s inactive the ganglia take over.”
Previously, scientists have hypothesized that insects display this behavior to more effectively retain water. But this seemed unlikely when the breathing pattern was found among insects in dry deserts and in the humid tropics.