Chemosignal Jammers Using Olfactory Mimetics

 

Camouflage isn't just blobs of brown and green colors, it's anything that interferes with perception. And because we can perceive via more than just the visual sense, mixing signals in any medium can help to obfuscate or redirect perception. "Protective auditory mimicry" adds sounds to your phone line that sound enough like human speech as to make your actual speech unintelligible. VS Ramachandran's Mirror Box, known for its use ridding phantom limb syndrome, uses a kind of signal jamming to rewire your brain's own proprioception of body parts. Maybe that's not camouflage, but it's close. And now, here's some examples of how smells are used for similar purposes:

Ladybug scents offer a more ecologically friendly way to protect crops

Feb 2024, phys.org

https://phys.org/news/2024-02-ladybug-scents-ecologically-friendly-crops.html

Aphids have a reduced preference for ladybug scented plants.

via Huck Institutes of the Life Sciences' Center for Chemical Ecology at Penn State: Jessica T. Kansman et al, Smelling danger: Lady beetle odors affect aphid population abundance and feeding, but not movement between plants, Basic and Applied Ecology (2023). DOI: 10.1016/j.baae.2023.05.004

https://dx.doi.org/10.1016/j.baae.2023.05.004

Unrelated image credit: AI Art - PCB Board Musician With Cat Face - 2025

Fooled: Herbivorous animals 'led by the nose' to leave plants alone

Feb 2024, phys.org

https://phys.org/news/2024-02-herbivorous-animals-nose.html

Seedlings of an unpalatable shrub in the citrus family called Boronia pinnata were planted next to a palatable canopy species called Eucalyptus punctata. The palatable species was 20 times less likely to be eaten by the swamp wallabies being tested.

Previous attempts to use repellent substances such as chili oil or motor oil have inherent limitations. "Animals tend to habituate to these unnatural cues."

via School of Life and Environmental Sciences Behavioural Ecology and Conservation Lab at University of Sydney: Olfactory misinformation provides refuge to palatable plants from mammalian browsing, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02330-x

https://dx.doi.org/10.1038/s41559-024-02330-x

Post Script:

Research uncovers why urine sprayed by cats emits a pungent odor

Apr 2024, phys.org

https://phys.org/news/2024-04-uncovers-urine-sprayed-cats-emits.html

In conclusion, feline sprayed urine originates solely from the bladder, without any contribution from other secretions. However, despite this exclusive source, sprayed urine emits a strong and pungent odor owing to enhanced adhesion on vertical surfaces.

The specific urinary protein, cauxin, plays a crucial role in scent marking by not only producing cat-specific odorants but also by enhancing the emission of urinary volatile chemicals by increasing the wettability of the sprayed urine.

via Iwate University: Sprayed urine emits a pungent odor due to its increased adhesion to vertical objects via urinary proteins rather than to changes in its volatile chemical profile in domestic cats, Journal of Chemical Ecology (2024). DOI: 10.1007/s10886-024-01490-1

https://dx.doi.org/10.1007/s10886-024-01490-1

Plume Tracking and Odor Mapping Algorithms

A deep reinforcement learning model that allows AI agents to track odor plumes

Feb 2023, phys.org

https://techxplore.com/news/2023-02-deep-ai-agents-track-odor.html

Insects track odor plumes to find mates. (And there was a similar study done recently here.)

"Instead of running a traditional laboratory wind-tunnel experiment, we used a complementary 'in-silico' approach using artificial neural networks," Singh explained. "This helped us develop an integrative understanding of plume tracking across multiple levels, including emergent behavior, neural representation and neural dynamics."

To train their plume-tracking agents using DRL, the researchers first simulated an odor emanating from a source located within a windy arena with a total area of approximately 120 m2. When their agents identified where the source of the odor was located, they received a reward. In contrast, if they lost track of the odor plume and left the arena, they were "punished."

"The behavior that emerges in our trained artificial agents bears a striking resemblance to the behavior modules biologists have previously observed in flying insects performing plume tracking," Singh said.

via University of Washington and University of Nevada: Satpreet H. Singh et al, Emergent behaviour and neural dynamics in artificial agents tracking odour plumes, Nature Machine Intelligence (2023). DOI: 10.1038/s42256-022-00599-w

https://dx.doi.org/10.1038/s42256-022-00599-w

Image credit: AI Art - Total Hallucination - 2023

Hyper-Hypo-Nose

Sounds like a big deal. Also sounds like a great explanation for the phantom "Iso E Super" anosmia that isn't a full anosmia.

Researchers reveal an added layer of nuance in our sense of smell

Jan 2023, phys.org

https://medicalxpress.com/news/2023-01-reveal-added-layer-nuance.html

They've discovered something called a depolarization lock to add to the standard combinatorial coding model used for odor detection, and it turns off the receptors when presented with high concentrations of an odor. 

You might already be familiar with this phenomenon for odors like violet and hydrogen sulfide (H2S). In the case of H2S, this receptor-deactivating behavior can be life-threatening, which is why you're supposed to wear a supplemental gas monitor, in addition to your nose, when entering areas suspected to contain high concentrations of the gas. 

^This write-up does a good job of explaining the fruit fly experiment that led to this discovery, as well as possible reasons why this would be needed for olfaction. 

via UC Santa Barbara: David Tadres et al, Depolarization block in olfactory sensory neurons expands the dimensionality of odor encoding, Science Advances (2022). DOI: 10.1126/sciadv.ade7209

https://dx.doi.org/10.1126/sciadv.ade7209

Image credit: AI Art - Cyberpunk Gasmask 2 - 2022

Post Script:

In addition to Iso E Super, Hedione is another perplexing odorant that's in almost every fragrance formulation from floor cleaners to face cream, and yet most people can't actually smell it. Well, you can smell when it's NOT there, but you can't smell when it is. (Old post mentioning Hedione)

And if I'm reading this correctly, it sounds like someone with a hypersensitive nose might be more likely to lose their sensitivity altogether. I seem to have some kind of hyperosmia myself, and yet when I go out to sample perfume, I often can't smell anything at all. Take the same perfume, put it on a strip of paper and leave it on a table in my house for the next 3 weeks, and I will smell the whole bouquet revealed one at a time as the mixture breaks down. The theory being that if you're hypersensitive to a specific odorant, or all odorants for that matter, your "depolarization lock" will kick in at low concentrations. 

Post Post Script:

Hella synonyms for the musky odorant referred to above, in fact so many that I just wanted to list them here: Iso E Super, Tetramethyl acetyloctahydronaphthalenes is a synthetic ketone fragrance also known as octahydrotetramethyl acetophenone (OTNE) and by other commercial trade names such as: Iso E Super, Iso Gamma Super, Anthamber, Amber Fleur, Boisvelone, Iso Ambois, Amberlan, Iso Velvetone, Orbitone, Amberonne. It is a synthetic woody odorant and is used as a fragrance ingredient in perfumes, laundry products and cosmetics.

-Hall, John B. & Sanders, James Milton, "Perfume composition and perfume articles containing one isomer of an octahydrotetramethyl acetonaphthone", issued 1975

https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US3929677

Darwin’s Children

Voldemort has nothing to do with Charles Darwin, or Greg Bear, but he has no nose.

Darwin’s Children, scifi book by Greg Bear, 2003

Children communicate by using psychoactive chemical scents made from their own bodies. A beautiful twist on the idea that smell is a vestigial organ or perception. At one point, a boy consciously secretes from his own body a mind-controlling scent, wipes it on sheets of paper, crumples them up and throws them at the seat next kidnapping bus-driver, who becomes overtaken by the boy’s vaporous emissions.