A study led by Nikita Komarov and Simon Sprecher at the University of Fribourg, Switzerland, has discovered neurons in the fly larva mouth that allow the taste of food texture. Published in the open-access journal PLOS Biology on January 30th, the study found that the fly peripheral taste organ has neurons with texture-tasting mechanoreceptors that derive their ability from the painless gene.
Most research on food sensation has focused on tastes like sweetness or saltiness. But preferences for food often depend on their texture; some might like the flavor of mushrooms, but not the rubbery feeling in their mouths. While tasting flavors requires chemical sensation, tasting texture requires mechanical sensation, and it is unclear whether taste organs like the tongue have this capacity. The new study addressed this issue in fruit fly larvae, commonly called maggots, because of the simplicity of their nervous system and the available genetic tools.
The researchers established that maggots will not eat food that is too hard or too soft, but if it is just right—corresponding to days old decaying fruit—they dig in. Hypothesizing that this ability to sense food texture takes place in the peripheral taste organs, the researchers selectively disabled taste neurons in the larva mouth. As a result, the maggots lost their sense of taste texture and tried eating food that was softer or harder than their usual preference. Further experiments revealed that the painless mechanoreceptor gene is required for this sense. Lastly, they found that the C6 neuron in the maggot taste organ can sense both sugar and mechanical stimulation, meaning that the same neuron can taste food texture and food substance. Taste sensation and signal integration is thus quite different from other systems, and investigations beyond fruit flies are needed to fully understand taste perception in mammals, including humans.
The authors add, "Food texture remains a neglected attribute of overall food fitness. We find - with the power of Drosophila genetics - that at least the hardness of food is a crucial aspect of the overall gustatory profile. Excitingly the same neurons that sense chemicals in the taste system can in some cases sense texture."
In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002730
Citation: Komarov N, Fritsch C, Maier GL, Bues J, Biočanin M, Avalos CB, et al. (2025) Food hardness preference reveals multisensory contributions of fly larval gustatory organs in behaviour and physiology. PLoS Biol 23(1): e3002730. https://doi.org/10.1371/journal.pbio.3002730
Author countries: Switzerland, Republic of Korea
Funding: This work was supported by the Swiss National Science Foundation grant 310030_219348 and IZKSZ3_218514 to SGS. The funder had no role in the study design, data collection and analysis, decision to publish, or preparation.
