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Things that insects know: can insects learn?

Until a few decades ago, insects were considered mindless automatons whose actions are guided by instincts and reflexes, but it turns out that they are also much smarter than was commonly thought

A bumble bee sucks nectar and in the process pollinates a flower. Photo: shutterstock
A bumble bee sucks nectar and in the process pollinates a flower. Photo: shutterstock

Moshe asks: Is it possible to teach insects?

Four are the small ones of the earth, and how wise are the wise: the ants are with no goat and they prepare to feed them in the summer.. There is no king for the locust and the whole of it comes out as a buffer.. ” (Proverbs chapter XNUMX).

Until a few decades ago, insects were considered mindless automatons whose actions are guided by instincts and reflexes. The brains of the insects are very small, only 960 thousand nerve cells make up the bee's brain and the fly is satisfied with 200 thousand so there is not much to teach. Life time is short so there is no time to learn and there is not enough time to take advantage of the learned material. Many important operations such as mating and spawning are performed by insects only once in their lifetime, so there is no opportunity to learn from mistakes. A learned insect, therefore, is nothing more than a waste of resources that frugal evolution would reject. The flea circuses, a popular attraction at the fairs of previous centuries, in which fleas drove miniature chariots and kicked a ball were not accepted, and rightly so, as real proof of learning ability. Indeed, the behavior of insects is largely dictated by instincts, an ant does not need study or training to dig burrows and a mosquito does not need special intelligence to sting us. But a series of studies on insects from different groups yielded the recognition that insects and even simple creatures are certainly capable of learning from them and that evolution has brought almost every creature with a nervous system some capacity for memory that allows it to adapt its behavior to past experience. So, for example, a fly that receives its food on a plate of a certain color will develop a preference for that color. Flies are instinctively attracted to light, yet flies that experienced a maze where a lighted path led to an encounter with a repulsive substance learned to choose the dark path, meaning that learning overcame instinct. Fly maggots learn to avoid lighting conditions or smells associated with "punishments" such as salt or repellent substances and there is evidence that the adult preserves memories it acquired while being a larva. In a manner reminiscent of humans, the learning ability of insects also decreases with age: one-year-old elderly cockroaches had great difficulty in learning tasks that young two-month-olds easily succeeded in.

The gifted in insects belong to the bee series (Hymenoptera, which includes the bees, ants and wasps. The bee is an extremely intelligent insect, its way of life requires it to process a great deal of information required to collect food and take care of the hive. The input from the sense of sight includes, in addition to our rainbow of colors, ultraviolet light and the polarization of light. The bee must accurately analyze details of shape, movement and symmetry in order to get along among her friends, her enemies and the abundance of flowers from which she must choose, she must recognize a wide variety of smells and thousands of sensory hairs on her body flow information about position and movement. All this information is concentrated in a tiny brain that swells About one cubic millimeter. It is amazing to discover that this tiny cluster of cells is not only able to absorb information and create muscle actions from it, but also to learn. The most impressive example of the bee's intellectual capacity was given by a team of researchers who showed that bees are able to "understand" the abstract concepts of identity and difference The researchers accustomed a bee to move along a route where it was first exposed to one stimulus (color, shape or smell) and then to an intersection where it had to choose between a similar or different stimulus to the one it was exposed to at the entrance. For example: if the entrance was painted blue, the bee had to choose whether to continue on a blue route or turn to the yellow corridor. When a sweet reward was waiting for a bee at the end of the corridor identical to the entrance room, the bees learned to continue on a yellow path after a yellow entrance gate and a blue path after being exposed to a blue gate. Other bees have been equally successful in changing color, shape or smell when that is what is required to get the sugar at the end of the road. But the wonders of learning did not stop here: a bee that learned to navigate the maze based on color was put into a new maze where the cue at the entrance was not color but shape (vertical or balanced lines) or smell (mango or lemon). It turns out that a bee that was trained to look for color identity navigated the new maze according to the identity of the bolt or in the direction of the lines and a bee that was trained to look for differences in colors turned to a corridor that smelled of lemon after a mango bolt gate (and vice versa). It turns out that the bee's miniature brain provides not only conditioned reflexes but also a much higher level of learning.

Why would insects invest resources in unlocking intelligence when their lives are so short and their minds are so small? The bewilderment increases in the face of studies that show that investing resources in learning has a high price in other areas that are essential for survival. Through repeated hybridizations of the successful ones in various "psychometric tests" it is possible to produce strains of flies that excel in learning and memory. When comparing the performance of the intelligent flies to their simple counterparts, it becomes clear that they survive less in conditions of lack of food and lay fewer eggs. What is the force driving evolution to waste energy on learning?

Instinct enables a good response to environmental stimuli and enables complex operations such as building a beehive or nest quickly and efficiently. But the instinct is only effective if the environment is constant over many generations. Insects such as bees or ants live long enough to encounter a changing environment (for example with the seasons), depend on a variety of food sources and are exposed to various dangers, instinct alone cannot manage. The "smart" insects are, and not by chance, the social ones. Social learning is the most economical in terms of the investment required to obtain useful information and is essential for the survival of bees, ants and other swarming insects. Darwin already admired a bee learning to reach nectar by piercing the flower's calyx from observing a bee of a different species. Observations of bees in their natural environment revealed that the cost of collecting food increases as the young worker learns from the veterans the most productive flower species and how to access the nectar. Social learning takes place in the hive when mouth-to-mouth contact with her friends allows the bee to identify the characteristic smell of the nectar they bring and thus produce a preference for those flowers and in the field as she observes and imitates. Bees have an innate color preference that directs them to the petals of flowers, but a bee will prefer an unattractive flower, its friends approach a flower whose color is tempting and other bees avoid it. Since the insect intelligence is hereditary and all the working bees are the daughters of one mother, it is possible to sort bee colonies according to their ability to learn just as they do for individuals. It was clearly found that bee colonies with good learning ability manage to bring more nectar to the hive than their stupid counterparts. Personality differences have been observed in cockroaches which are manifested in the ability to learn orientation in a maze: if the cockroach managed to avoid the flip flop you may have been visited by a gifted cockroach. An even higher level of learning ability was demonstrated in bumble bees, bees were placed in a facility where they received a sweet reward when they successfully rolled a ball to a target point. The mere act of moving an inanimate object to achieve a goal may be considered a considerable intellectual achievement, and what distinguishes success from mere operant conditioning is thatBumble bees learned faster when they were exposed to other bees who had already learned the trick and to a lesser extent than when the ball was rolled to the target by an artificial bee.

Similarly, cricket larvae not exposed to predators learned to hide under leaves when exposed to "experienced" larvae that had already experienced predation events near them. With ants, social learning reaches its peak: ants not only learn from their friends by watching and imitating, but also take the trouble to teach their sisters to the nest. Behavior aimed at teaching others (and not just allowing them to imitate) is rare in the animal world: although it is likely that there are other teachers in nature, apart from humans and ants, there is conclusive proof of such behavior only in African mongooses (sericotes). The teaching ant guides its friends to a food source as it runs back and forth and adjusts its speed to that of the students (the dance through which a bee gives information about the direction and distance of a food source is not considered teaching because it will be performed even without the presence of students).

Even the sexual activity in insects turns out to be learnable: fruit flies (Drosophila) learn from their experience to recognize the females of their species and thus avoid fruitless effort in courting flies belonging to similar but different species. Learning can even overcome genetics: Drosophila males that underwent a mutation that deprived them of the ability to court learned to court when raised in a mixed group with normal males. In females, early acquaintance with males makes them more picky and in spiders also more efficient in cannibalism: eating the partner who fulfilled his role.

 Almost 400 years since the philosopher Descartes took a soul from the animals, it becomes clear that it was King Solomon who saw the smallest of the land and especially the social ones as "intelligent sages" closer to the position of modern science that recognizes the ability of natural selection to produce feelings and learning ability.

thanks to :

 Dr. Luc-Alain Giraldeau, Dr. Sheena Brown, Dr. Thomas Valone, Dr. Eric Le Bourg,

Dr. Reuven Dukas, Dr. Walter Farina, Dr. Lars Chittka for their help

Did an interesting, intriguing, strange, delusional or funny question occur to you? sent to ysorek@gmail.com

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Comments

  1. The whole idea of ​​CRISPR is a discovery about the memory of the immune system of bacteria. So if germs can learn why not insects?

  2. Fascinating as ever.
    But speaking of insects why not mention more primitive families like molluscs and worms.
    Do they also study? Do their brains have fewer neurons? Which creature has the simplest nervous system?
    And is there learning even without a central nervous system?
    Can't bacteria learn?

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