The most “scientific” fly turned out to be the most “cultured”

Magnus Moore. A typical day at the Leaning Tower of Pisa

Cultural behavior is characteristic of all living things. With a person, more or less everything is clear. But it turns out that cultural behavior is inherent in all biological species. In particular, even such a tiny and seemingly primitive creature like the “great scientific fly”. Its contribution to understanding human culture may be as great as the contribution to genetic research.

LIFE INVISIBLE TO THE WORLD

The scientific significance of this tiny fruit fly cannot be overemphasized. Its size is only 2-3.5 mm, that is, 10 times smaller than the usual fly. The eggs laid by Drosophila are about 0.5 mm. They are almost invisible, which gives the impression that flies appear out of nowhere.

As if by themselves. Today, scientists know more than 1000 species of Drosophila flies. Most of them live in the tropics and subtropics, where they feed on plant sap and their remains. There are about 300 of them in Hawaii.

Fruit flies have a voice – they squeak and, apparently, in this way communicate with each other. But this squeak is indistinguishable to the human ear. The invisibility of the appearance of fruit flies since ancient times was one of the proofs of the theory of spontaneous generation of life.

SELF-GENERATION THEORY

The theory of the spontaneous generation of the living from the inanimate was popular in ancient times in Egypt, Babylon and China. It was adhered to by Aristotle, who argued that any wet body, becoming dry, gives rise to living organisms. That is, animals and plants can “spontaneously” in inanimate matter, and not only by mating or developing from larvae and seeds. In symbiosis with the teachings of the church fathers, Aristotle’s theory provoked the most daring ideas.

For alchemists, frogs arose from dew, birds – from branches and fruits, and by mixing different chemicals in a flask, it was even possible to bring out an artificial person – a homunculus. The theory of spontaneous generation was considered for some time as an alternative to the divine creation of the world. However, in 1688, an Italian biologist experimentally proved its inconsistency.

This is how the concept of biogenesis arose, which is that living things can only be generated by living things. However, the scientific controversy did not end there … In 1859, the French Academy announced the award of a prize for the final proof or refutation of the possibility of spontaneous generation of life. Louis Pasteur received this prize in 1862.

THE GREAT SCIENTIFIC FLY

Drosophila flies were one of the last bastions of the theory of spontaneous generation, collapsed after a series of scientific discoveries. However, their importance for science not only did not decrease, but, on the contrary, increased. Drosophila has become an invaluable object of genetic research. Analysis of the human and Drosophila genomes revealed that more than 70% of the human and fly loci coincide.

 And nowadays, the number of fruit flies involved in genetic experiments around the world is comparable to the number of people on Earth. Lots of  Nobel laureates owe their prizes to the fly. To date, the genomes of 12 species of Drosophila have been fully read – this is perhaps the most studied living organism on the planet. The Institute for Molecular Pathology in Vienna is close to decoding the entire genome and creating a worldwide catalog of fruit flies.

WHAT DOES GENETICS SMELL LIKE?

The incredible popularity of flies among scientists is due to their short development cycle (10 days from the moment of oviposition) and high fertility (from 50 to 200 offspring from one pair). This makes it possible to quickly track genetic mutations. Laboratory studies of fruit flies are completely safe, but rather unpleasant for sensitive natures.

The nutrient medium for them is usually a mixture, which includes: corn flour, yeast, malt additive and beetroot syrup. Everything smells rather unusual for a person. But it is through such solutions that drosophila are fed various substances that cause mutations. The life span of a laboratory fly is about 2 months, during which it actively feeds and reproduces under the supervision of scientists.

SPACE ODYSSEY

In addition to humans, Drosophila, perhaps most often of all living things, leaves the planet. It flew to the moon on special probes, traveled on manned ships and satellites. As a result, creatures born in zero gravity were obtained – “ethereal creatures”, as Tsiolkovsky called them in his time.

I must say that in addition to fruit flies, many animals and plants have visited space: monkeys, cats, dogs, mice, turtles, frogs, snails, quails, newts, various flowers and cereals … True, the first “ethereal creatures” were not fruit flies at all, but descendants of a ginger cockroach named Nadezhda, which from September 14 to 26, 2007 with pleasure reproduced on an unmanned spacecraft “Foton M-3”. Experiments with fruit flies have confirmed that any living creatures, not only cockroaches, can live and reproduce in space.

FEATURES OF FlIES SEX

Despite the fact that Drosophila, it would seem, has been studied up and down, it nevertheless sometimes manages to surprise scientists. Culture, understood as the stable inheritance of behavioral traits through social learning, has not been considered a unique human trait for 70 years. By studying social learning and cultural traditions in fruit flies, French scientists have recently discovered that they have the ability to copy mate choice.

That is, observing how other females mate with males with a certain phenotypic trait, females in the future begin to prefer just such males. “Since she chose him, it means that there is something in him after all,” – apparently, somehow the female fruit flies reason. But the surprises did not end there.

LOSERS PREFER VIRGINS

It turned out that the female Drosophila decides how to react to male courtship, taking into account a lot of factors. So, virgins were less selective than females with sexual experience. But after the first mating, they become more picky and prefer males that produce a lot of pheromone.

Moreover, the female always rates her first sexual experience as either positive or negative. Males do the same: after the experience of unsuccessful courtship, males begin to prefer “promiscuous” and picky virgins. And more experienced males take care of females more actively and successfully than young ones.

WITHOUT CULTURE – IT IS IMPOSSIBLE TO SURVIVE!

Why is such research important? Today, the UN Environment Program insists that animal culture should be protected as much as genetic adaptation. This is very important for the survival of the species. Of course, it is most convenient to study the cultural characteristics of biological species on Drosophila under laboratory conditions. However, there are other experiments of this kind.

Humpback whales have cultural traditions associated with sound communication and migration routes. In one community of chimpanzees, scientists witnessed a tradition of sticking a blade of grass in their ear. Song dialects of birds change over time, contributing to speciation. Bonobos in neighboring communities have different hunting traditions: different groups hunt different game.

Inexperienced fish learn to recognize predators and avoid them by observing the behavior of their relatives. All this allows us to raise the question of humanity, whose cultural behavior is incredibly complex and diverse. Obviously, it was this feature that made Homo sapiens the dominant species on the planet. It turns out that the reduction to one cultural norm, simplification and primitivization of culture reduces the chances of the human population for survival.