Karen Hopkin: That is Scientific American’s 60-Second Science. I’m Karen Hopkin.
Hopkin: Some sounds are spooky [ghostly yowl?]. Some are disagreeable [screechy blackboard? Vinyl album scratch?]. And a few are totally unsettling. [creaking door? Scream? Discordant psycho-shower-scene type music?].
However some sounds…some sounds…are like nothing you’ve ever heard earlier than…and nothing you’d ever need to hear once more.[Sound of 2-hydroxybenzaldehyde]
THAT was the sound of 2-hydroxybenzaldehyde. And in case you’re considering, maintain on, molecules don’t make noise…nicely, you’re proper. However that discordant nightmare was an audible soundscape that represents the chemical properties of 2-hydroxybenzaldehyde.
What’s much more eerie, is that whereas that sound might have made you need to crawl out of your pores and skin and skitter in direction of the door, the chemical itself has an analogous impact on ants. That’s in line with a examine within the journal Patterns.
Jean-Luc Boevé: The world of bugs is stuffed with chemical compounds.
Hopkin: Jean-Luc Boevé of the Royal Belgian Institute of Pure Sciences in Brussels.
Boevé: Thomas Eisner…who arrange the sphere of chemical ecology… stated that the bugs are…one of the best chemists on earth. And he stated this as a form of joke however he was completely true in saying this as a result of bugs are producing wealthy quantities of various chemical substances for various functions.
Hopkin: Together with preserving themselves and their households protected.
Boevé: Many different insect teams are producing volatiles and different compounds to defend themselves towards predators.
Hopkin: Like an overwhelming fragrance, these risky secretions waft by means of the air and irritate critters who is perhaps considering of noshing on the bugs that produced them. Boevé, specifically, research the larvae of sawfly species, which produce totally different cocktails of chemical substances that act as a repellant, particularly towards ants.
However Boevé isn’t solely an entomologist. He’s additionally an beginner musician. And he received to considering, nicely, smells transmit a sign by drifting by means of the air…and so do sounds.
Boevé: I assumed that it might be fairly fascinating to go deeper into this parallel between the notion by way of two totally different sensory methods particularly smelling and listening to. So the concept was to transform these volatiles into sounds. Then…to match, on the one hand, predators reacting towards the volatiles with, then again, people listening to sounds that characterize these volatiles.
Hopkin: The 1st step was remodeling aroma into audio. To try this, Boevé and his colleague Rudi Giot of the Greater Industrial Institute of Brussels turned to a course of known as sonification, which interprets chemical parameters into sounds.
Boevé: The chemical parameters that we used as an illustration it was the molecular weight of compound, or the truth that the compound possesses or not some practical teams. By practical group I imply an alcohol group or ketone group or aldehyde group or acid group.
Hopkin: These molecular properties have been then mapped to musical qualities, like pitch and tone, length and timbre, even reverberation.
Boevé: Doing so we constructed up a library of the molecule sounds obtained by changing every molecule into one sound.
Hopkin: So acetic acid…principally a concentrated vinegar…feels like:[Acetic acid sounds]
…whereas geranial, an isomer of citral, which is a essential element of the oil in a citrus fruit’s peel, sounds extra like:[Geranial sounds]
Hopkin: Boevé isn’t the primary to make use of sonification to transform chemical knowledge into audio waves. As early because the Nineteen Seventies, geneticists have been remodeling the 4 letters of DNA sequences into tunes that have been, nicely, not precisely chart-topping.
Boevé: The sounds have been…not very good, not very wealthy. As a result of when you’ve got solely 4 tones, then the music or the sound that you simply hear are…very monotonous.
Hopkin: The insect irritants have been rather more fascinating…as a result of every species produces its personal signature chemical mix. Boevé and Giot mimicked these molecular mixtures by taking the person chemical sounds and mixing them collectively on a sound board…utilizing totally different volumes to characterize the concentrations of compounds in every species’ poisonous concoction.[Locust sawfly larva sounds]
Hopkin: That’s the chemical stylings of Nematus tibialis, a locust sawfly larva. Which is heavy on the dolichodial, a vital oil that some vegetation use as an insect repellant.[Dolichodiol sounds]
And this pungent tune helps preserve Hoplocampa testudinea, the European apple sawfly, from being eaten.[European apple sawfly sounds]
Hopkin: However that’s simply the setup. Then got here the experiment. Boevé uncovered ants to the precise chemical substances…both individually or in mixtures…and recorded how completely the predators have been repulsed by every. And for the sonified sounds…volunteers would play clips…of single molecules or mixtures…and hearken to the sounds from a pair of loudspeakers.
Boevé: Then we requested them to go backward, stroll backward till they have been at a consolation zone. And I used to be measuring, I used to be noting the gap that they walked backward.
Hopkin: And he discovered that the molecules and mixtures that have been most annoying to ants have been the identical ones that, when sonified, precipitated volunteers to retreat.
Boevé: And lots of informed me that some sounds have been fairly horrifying and that’s why they went backward.
Hopkin: However Boevé isn’t in it for the scares. The correlation between a chemical’s impact on ants…and a sound’s impact on folks…signifies that he can use sonification to review the defensive scents of recent species…or species for which it is perhaps laborious to scare up a specimen.
Hopkin: Scare up? Get it?[Blood-curdling scream]
Hopkin: For Scientific American’s 60-Second Science, I’m Karen Hopkin.[Mix of insect defense sounds] [The above text is a transcript of this podcast.]