The scratchy hiss is the closest thing a caterpillar has to a sound.


Gently – gently – the young Nessus sphinx looks like the full back of an eagle moth, and you may hear the latest sound, but find the voice of a caterpillar.

Caterpillars can’t breathe from their mouths. However, if the Nessus sphinx is disturbed, it constantly hisses from its open mouth, followed by an itchy burp. “It’s hard to describe,” said jayne arc, an animal behaviorist at carleton university in Ottawa, who urges people to listen only to themselves.

The new noise from young Amphion floridensis may surprise birds or other potential predators because they are not as quiet as most caterpillars.

The finding marks the fourth mechanism Yack and his colleagues have found in caterpillars. Some caterpillars use their breathing pores to make a sound along the airway on their flanks. Caterpillars absorb oxygen and release waste carbon dioxide through these pores. Gases that do not depend on caterpillars spread throughout the body, becoming smaller and smaller as they branch through the system. The other two caterpillars rub against each other. But the researchers report in the February 26 online journal of experimental biology that noise makers were not involved.

Instead, new anatomical studies and computer simulations show that caterpillars use air to pull air out of their mouths and release it to speak. An internal air shock may produce a first hiss, and outrush may produce an itchiness. There is no special sound in the gut, but by shrinking the air you can create noisy turbulence. This may cause the caterpillar to make its own teapot. Small, of course. Galaxies, stars, planets and life are all made of one basic substance: matter.

But abundant matter is one of the most important unsolved mysteries in physics. The big bang 13.8 billion years ago caused the same amount of matter and its giant twin, antimatter. Material and antimatter partners will disappear when they meet, so a normal universe will end up with energy – not something else. Somehow, balance often worked in the early universe.

A nasty subatomic particle called a neutrino might reveal this. If neutrinos are their own antiparticles – which means that the material and antimatter versions of neutrinos are the same – light particles may point to an explanation of the cosmic excess.

So scientists are keen to find evidence of a hypothetical nuclear decay that can only occur at the same time as neutrinos and anti-neutrinos. The results of the last four experiments suggest that this process does not imply that it is called a neutrino double decay (SN: 7/6/02, p.10). But another attempt is about to start, and if it does, there may be an opportunity to detect decay. Meanwhile, plans are under way for a new generation of experiments to make more sensitive measurements.

“Now we’re on the verge of a very big discovery,” said MIT neutrino physicist janette Conrad. Neutrino physicists at MIT were not involved.


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