American neuroscientists have discovered a new way of collective orientation of electric fish. It was previously believed that increased impulses could interfere with relatives, but it turned out to be the opposite.

In addition to the senses we are familiar with (sight, hearing, smell, taste and touch), some fish have the unique ability to sense electrical fields, that is, electrosensing. This ability has also been found in platypuses and echidnas, but is much more common among aquatic animals. For example, electricity has also become a weapon for eels and rays; Eels are capable of producing a discharge of 860 volts, almost four times more than a regular outlet.

But fish mostly use electricity to communicate, courtship, search for food, and navigate space; Vision is not as effective in murky water. But to ensure that this ability does not interfere with communication, as previously thought, electric fish change their pulse frequency when near their relatives. So they avoid obstacles. It has also been suggested that cues from relatives increase spatial orientation for dolphins and bats, which communicate and navigate using a unique sensory mechanism.

Two neurobiologists from Columbia University (USA) decided to find out whether kin proximity helps fish with electroreceptors navigate. For this, the authors chose the Peters gnatonema (Gnathonemus petersii), is also called the Nile elephant because its lower lip resembles the trunk. Researchers studied the behavior of fish in a group with the help of computer simulations and aquarium experiments and found that the collective production of electrical impulses improved the ability to study the environment. An article on this subject was published in the magazine. Nature.

The authors created models of mosquito behavior based on video observations of groups of fish in which one individual was dominant and two were subordinate. Detection of an object in gnatonema occurs as follows: The fish emits an electrical signal, and receptors on its body register its reflection from the object. In this way, the fish understands where and how close the object is to it. The researchers found that when there was another gnatonema next to the object (in the experiment, it was a one-centimeter ball), the “picture” of the signal reflected from the first fish was clearer. And, as the authors note, the detection range has tripled.

Neuroscientists then began testing how the presence of a relative would affect the fish’s behavior. A large aquarium filled with various objects was placed inside the gnaton, and an artificial model played the role of the relative, emitting pulses with a frequency of 10 Hz when a button was pressed. Although the fish could move freely in the aquarium, they spent most of their time almost motionless near their relatives, the authors wrote. The sensory range of the fish increased when artificial gnatonema was also included.

In addition, the presence of another fish accelerated the transfer of information; Electrical impulses between conspecifics are transmitted at intervals of approximately 12 milliseconds, and between a single gnathonema and an object at intervals of 50 to 200 milliseconds. As the authors of the article emphasize, the obtained results demonstrate a new method of collective orientation of electric fish.