Why do fruit flies feel hungry? Because of cockroach amine.

Fruit rots for a long time and fruit flies come unasked. There is a set of sophisticated and complex mechanisms behind this behavior. Wang Liming’s team of the Academy of Life Sciences of Zhejiang University found for the first time a molecule, cockroach amine, which regulates the foraging behavior of fruit flies in animals by reproducing their foraging behavior in the laboratory. Without this molecule, fruit flies would not find food even if they were hungry. This opens the tip of the iceberg of the mystery of eating.

When you feel hungry, food you don’t usually like will also feel very fragrant. “The biggest concern of our laboratory is how animals perceive hunger and what they do when they are hungry.” Wang Liming said that this process includes at least two independent steps: first, the brain detects biological signals in the body, and judges that there is insufficient energy or nutrients in the body; and second, the emotional and behavioral reactions caused by it.

Drosophila is one of the most popular model organisms among scientists. How to judge that fruit flies are hungry? The research group chose “foraging” as the judgment sign. There are three key characteristics of foraging: increased activity, obvious purpose and accompanying strategy selection. These three are all satisfied on the Drosophila hunger model established by the research group. What is particularly interesting is that fruit flies, like humans, behave relatively rationally when they are full, while hungry fruit flies are experiencing a large-scale “hunger-free” behavior.

Researchers have found a neurotransmitter, cockroach amine, which is structurally similar to norepinephrine in humans. “We found that without cockroach amine, hungry Drosophila flies would not have foraging behavior, even if their physical functions were intact and normal, and there was no movement disorder.” Scientists have judged that cockroach amine is a key molecule in hunger-induced foraging behavior.

For researchers, this latest study also reveals a richer connotation behind “foraging” and “eating”. “It is generally believed that hunger is detected through a single nerve center and triggers a series of emotions and behaviors. But our research suggests that, at least in drosophila, when the brain feels hungry, triggering foraging and triggering feeding may be two completely independent systems. The absence of cockroach amine blocked the feeding behavior of Drosophila melanogaster, but did not block its feeding behavior. Like two nerve pumps, one is destroyed and the other is functioning properly. Wang Liming said.

Wang Liming said that the study of eating is actually a study of how the brain detects signals within the body and makes a series of reactions. Discoveries in fruit flies can really help us understand the human brain, how we feel hungry, how we decide when and where to eat what foods, and why we find it hard to resist the temptation of delicacy and how to maintain healthy and reasonable eating habits.

“Despite the huge differences between small fruit flies and humans, how to feel hungry and how to find food should be the basic function to ensure the survival and reproduction of animals, and there may be highly conservative regulatory mechanisms on the evolutionary path.” Wang Liming said that he expects this study to help us better understand the human brain and one day help us understand the pathogenesis of metabolic diseases, including anorexia and bulimia.