Scientists have discovered that fruit fly larvae can actually “taste” food texture, thanks to specialized neurons in their mouthparts.
By disabling these neurons, researchers found that the larvae lost their ability to judge food hardness, attempting to eat things they normally wouldn’t. Surprisingly, the same neurons that detect sugar can also sense mechanical properties like food texture. This discovery suggests that our understanding of taste is more complex than previously thought, opening the door to further research in humans.
Neurons That Taste Food Texture
Scientists at the University of Fribourg in Switzerland, led by Nikita Komarov and Simon Sprecher, have discovered that fruit fly larvae can detect food texture using specialized neurons in their mouths. Their study, published in PLOS Biology on January 30th, reveals that these neurons, located in the larvae’s peripheral taste organs, contain mechanoreceptors that sense texture. This ability is linked to the painless gene, which plays a key role in their function.
While most research on taste focuses on flavors like sweetness or saltiness, food texture also shapes eating preferences. For example, someone may enjoy the taste of mushrooms but dislike their rubbery consistency. While flavor perception relies on chemical signals, texture detection requires mechanical sensation, and it remains unclear whether taste organs like the tongue have this ability. To explore this, researchers studied fruit fly larvae—commonly known as maggots—because of their simple nervous system and the availability of powerful genetic tools.
Maggots and Their Texture Preferences
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.
Reevaluating Food Texture in Taste Science
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.”
Reference: “Food hardness preference reveals multisensory contributions of fly larval gustatory organs in behaviour and physiology” by Nikita Komarov, Cornelia Fritsch, G. Larisa Maier, Johannes Bues, Marjan Biočanin, Clarisse Brunet Avalos, Andrea Dodero, Jae Young Kwon, Bart Deplancke and Simon G. Sprecher, 30 January 2025, PLOS Biology.
DOI: 10.1371/journal.pbio.3002730
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.
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