Flies are formidable insects: like other animals, they can distinguish between different flavors thanks to a series of "hairs" all over their bodies, including their legs and mouths, which they use to taste. That is, if they step on something with a flavor they find pleasant, they lower their mouths and taste it again. Now scientists have discovered that their ability goes beyond the classic sweet, salty, bitter, and sour tastes. They can also taste alkaline. The results have just been published in the journal Nature Metabolism. The research was carried out on the fruit fly Drosophila melanogaster, a model organism commonly used in laboratories (not surprisingly, it is the only animal to win five Nobel Prizes). It is used to study the mechanisms by which living beings perceive flavors. In other words, it can lay the groundwork for understanding the behavior of other species, including humans. The sense of taste influences animals' decision-making when choosing what to eat, as it allows them to taste the food before consuming it. Foods have pH, which is a measure of their degree of acidity or alkalinity. This parameter is measured on a scale of 0 to 14: in this ranking, 7 is considered neutral; anything below that is considered an acidic substance (for example, on average, tomatoes have a pH of 4 and coffee 6); and anything above that is considered an alkaline substance (for example, egg yolk or garlic). Related News standard No Male fruit flies 'drug' the female to make her fall asleep and not copulate with others ABC Science Males inject a peptide during ejaculation that is also known to cause females to not mate for days So far, taste receptors have been identified for acids (but not for bases (the name given to alkaline substances). Yali Zhang and colleagues at the Monell Chemical Senses Center (Philadelphia, United States), a center specialized in taste and smell research, discovered that when given a choice between neutral and alkaline foods, free-ranging flies prefer neutral foods and avoid alkaline foods. "While it is generally accepted that animals use sour taste to evaluate the acidity or low pH of foods, whether animals have a taste modality to sense the basicity or high pH of foods is a long-standing open question. Since acid, or low pH, has a sour taste, it would be logical to assume that base, or high pH, also produces a taste sensation,” the authors write. Previous studies have provided clues that alkaline taste may exist. In the 1940s, it was shown that in humans, the tip of the tongue is more sensitive to sodium hydroxide (NaOH) than the mid-dorsal part of the tongue, which has few taste buds, implying that basic solutions may have gustatory qualities. Furthermore, there is work suggesting that insects such as beetles avoid alkaline environments because they associate them with unfriendly habitats or few food sources. However, these are all clues, but the exact mechanism is unknown. Like mammals, fruit flies use different classes of taste receptors to detect sugars, salts, acids, bitter substances, and other chemicals. Since flies have such a remarkable ability to detect a wide range of substances through taste, the authors sought to prove that they could also sense the alkalinity of foods. Mutant Flies The researchers conducted a simple experiment: they presented flies with two foods, one neutral and one alkaline; the fruit flies showed a clear preference for the neutral food. They then selected a few genes that they believed might be involved in this preference. They found the alkaliphile gene (alka). To prove that it was responsible, they created 'mutant' flies by inactivating this gene and then subjecting them to the same experiment as the wild flies: these new flies had trouble distinguishing the alkalinity of foods. "The ability to taste alkaline substances could provide a beneficial adaptation for flies, given the adverse effects of highly alkaline pH on their development, survival, and lifespan," the authors note. «Detecting alkaline substances can help flies avoid ingesting toxic substances and stay away from pathogens that thrive in alkaline environments,» they suggest. MORE INFORMATION news No These are the suits NASA will wear back to the Moon, which are being 'rented' by a Spanish company news Yes No all meteorites brought water to Earth As for whether this ability to 'taste' alkaline foods can be extrapolated to other animals, Zhang indicates that more research is needed. We will have to wait to see if humans, like flies, can also perceive this taste.
