Researchers translate insect defense chemicals into eerie sounds

Date:
September 23, 2021
Source:
Cell Press
Summary:
Sawfly larvae protect themselves by secreting cocktails of
unpleasant, volatile chemicals intended to repel predators,
particularly ants.

Researchers can assess the effectiveness of these defenses by
staging meetups, so-called bioassays, between prey and predator. But
entomologist have taken a different approach, translating the
secretions' chemical composition into sounds, and measuring how
humans react.



FULL STORY ========================================================================== Sawfly larvae protect themselves by secreting cocktails of unpleasant,
volatile chemicals intended to repel predators, particularly
ants. Researchers can assess the effectiveness of these defenses by
staging meetups, so-called bioassays, between prey and predator. But entomologist Jean-Luc Boeve' and informatics engineer Rudi Giot have taken
a different approach, translating the secretions' chemical composition
into sounds, and measuring how humans react.

Their work appears September 23rd in the journal Patterns.


========================================================================== Boeve' and Giot quantified how unpleasant the sounds were to the
human ear by measuring how far back each subject walked to reach a
"comfort distance" away from loudspeakers. Part of the approximately
50 participants described some of the sounds as unpleasant or even
frightening. The sounds may be comparable to short excerpts from the
background music in a horror or science fiction film.

"Interestingly, we could show that the responses by ants and humans
are correlated, thus indicating that sonification can approximate the
'real world' of predator-prey interactions," says Boeve', of the Royal
Belgian Institute of Natural Sciences, in Brussels.

He first conceived the idea of transforming volatile chemicals into sounds
back in April 2009. "For instance, you have small molecules like acetic
acid contained in vinegar or pungent formic acid emitted by some ants,
they're very volatile and diffuse into the air rapidly," he says. "So,
I thought it would be possible to translate a high or low volatility
into high or low tones, as well as other chemical traits into other
sound traits." Chemicals are transformed into sounds using a process
called sonification.

Important characteristics of each molecule, like its molecular weight
and what functional groups it has, are mapped onto different parameters
of sound, like pitch, duration, and timbre. The chemical information is
fed into a synthesizer which produces a sound for each molecule and these sounds are then mixed at various volume levels to construct a sound for
the defensive secretion of each insect species.

This study takes advantage of the fact that our brains process
information differently depending on what sense we use to perceive
it. "Typically, a sonification process is used to detect particular
phenomena in large datasets," says Giot, of the Institut Supe'rieur
Industriel de Bruxelles. "Examples of such phenomena are earthquakes
in seismologic data, or network hacking in internet data streaming."
This project required years of laying down groundwork and completing
other more classical experiments, including chemical and morphological
analyses of the insects. "To be honest, I considered the sonification
project so far-fetched myself that I set the project aside, sometimes
for several months," says Boeve'.

He hopes that his method will be complementary to already existing
techniques of testing volatiles, especially in cases when an insect's
seasonal availability is unfavorable or harvesting large enough quantities
of its secretion is challenging.

========================================================================== Story Source: Materials provided by Cell_Press. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Jean-Luc Boeve', Rudi Giot. Chemical composition: Hearing insect
defensive volatiles. Patterns, 2021; 100352 DOI: 10.1016/
j.patter.2021.100352 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210923115607.htm

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