Moth wings reveal an unexpected ability to smell plant chemicals
Insect wings are bristling with senses, feeling the wind blowing and even tasting potential mates, but little was known about whether moth wings are equipped with a sense of smell. Sonja Bisch-Knaden ...
Insect wings are bristling with senses, feeling the wind blowing and even tasting potential mates, but little was known about whether moth wings are equipped with a sense of smell. Sonja Bisch-Knaden and Bill Hansson from the Max Planck Institute for Chemical Ecology, Germany, had a hunch that moth wings might be able to sniff out certain aromas.
Taking a close look at the surface of tobacco hawkmoth (Manduca sexta) wings and measuring the electrical signals produced by the wing, Bisch-Knaden and colleagues report in Journal of Experimental Biology that the moth's wings have a sense of smell and can sniff out the plants on which they lay their eggs.
Searching for scent hairs
Bisch-Knaden says, "The tobacco hawkmoth was recently found to have receptor proteins in its wings that could detect different smells and tastes." But receptor proteins are only the beginning of the sensory cascade that converts scents into nerve signals to transmit the sense of smell. She knew that tobacco hawkmoth wings would also require specialized odor-sensitive hairs distributed along their edges to have a true sense of smell. The team looked for the essential scent hairs.
After gently snipping the edges from tobacco hawkmoth wings, Ahmed Ismaieel (Max Planck Institute for Chemical Ecology) carefully sprayed a fine mist of gold over the sections before scrutinizing them with a scanning electron microscope.
Interspersed between slender (120 μm) touch-sensitive hairs, Ismaieel could see stubbier (80 μm) porous hairs, the hallmarks of scent sensors, suggesting that the shorter hairs might contribute to the insect's sense of smell. But could the wings actually sniff an odor?
Signals from the wing edge
To begin answering the question, Ismaieel and Regina Stieber, also from the Max Planck Institute for Chemical Ecology, collected mRNA from the insects' wings (which codes for the proteins that recognize specific scents).
After months of painstaking analysis, they identified the mRNA for 33 taste and scent receptors, with the mRNA for 15 receptors produced along the wing's edge, where the odor-sensing hairs are located. When the team cross-referenced the receptor proteins they had found in the wing with the odors that the receptors sense in other insects, they concluded that the moth's wings likely sense bitter flavors and the aroma of amines, which smell like rotting fish to us.
But which odors could tobacco hawkmoth wings sniff out in practice?
Only two odors stood out
Ismaieel rigged up a wing to an electrical circuit and blew puffs of odors—from putrid pyridine and fruity methyl hexanoate to the heady scent of Datura flowers—onto the wing to find out which scents the wing could smell.
Surprisingly, the wing only picked out two odors, pyrrolidine and piperidine, both of which are stinky amines found in the leaves of nightshade plants, on which tobacco hawkmoths prefer to lay their eggs.
When Ismaieel trimmed the edges off the wings and retested their sense of smell, he found they could still detect the unpleasant amine odors. "This suggests that the moth has special sensory hairs across its wings, not just along the edges, that can smell those odors," says Bisch-Knaden.
AI points to likely receptors
But which receptor proteins could be responsible for the wing's sense of smell?
This time, Ismaieel turned to AI to predict the 3D structures of 10 of the potential odor-smelling proteins before attempting to fit pyrrolidine and piperidine—the two molecules that the wing can smell—into the receptor protein pockets, allowing them to mediate the sense of smell.
Ismaieel got hits. Both of the stinky molecules fitted snugly into the binding pocket of two of the candidate receptor proteins, which could allow the proteins to trigger the sense of smell. So, tobacco hawkmoth wings definitely have a sense of smell, which could help direct them to their favorite plants for laying eggs.
Publication details
Ahmed Reda Ismaieel et al, Noses on the wing: the olfactory capacity of hawkmoth wings, Journal of Experimental Biology (2026). DOI: 10.1242/jeb.252047
Who's behind this story?
Swati Mestri holds a bachelor's degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space. Full profile →
Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →
Citation: Moth wings reveal an unexpected ability to smell plant chemicals (2026, July 27) retrieved 27 July 2026 from https://phys.org/news/2026-07-moth-wings-reveal-unexpected-ability.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.