Animal behavior can influence substance secreted by special glands in the external environment - pheromones. The word "pheromone" is translated from Greek as "transferring excitation" (phero - to bear, carry + hormao - to set in motion, impel).
There are two types of pheromones. The pheromones of the first type trigger certain behavioral responses. They are called releasename. This is usually vysokoletuchie substances that spread through the air and are caught by their olfactory organs of animals. The pheromones of the second type are transmitted by contact, for example, by slideways one insect from another body. Their impact is the change in the physiological condition of the animals or the change of its development. Such pheromones are called primers.
Pheromones-relizer cause immediate behavioural response. These pheromones are sexual attractants (attracting substances) some butterflies, and "taps traces" and "factors of anxiety", released by the ants and bees. For example, the bee alarm pheromone is released with poison in that moment, when the bee stings the enemy, and serves as a danger signal to other bees. Other volatile pheromones are used to mark the way to a food source. Ants, for example, trying to go along the trail, which was noted by the pheromone previously passed here scout ants (its width is about 1 cm).
Pheromones-primers have a slower action. They can slow down and even to suppress any physiological process, such as development of some organ.
For example, the action of hormone-primer. In insect colonies functions procreative often lie on the same insect uterus. The other members of the colony who perform a work, the sexual organs are atrophied. But should disappear the uterus, as in individual insects these organs begin to grow rapidly! It turns out that it's all in the pheromones that regulate the function of procreation. Special pheromones that are secreted by the uterus, slideways with her body other members of the colony. As a result, they suppressed the development of the genital organs. When the action of pheromones is terminated, the organs of reproduction begin to develop. This pheromone is a sex attractant for the male bees, the drones during mating flight.
The first information about the presence of insects peculiar smells, from afar able to attract individuals of the opposite sex, appeared almost a century ago. Famous French entomologist Henri Fabre (1823-1915) found that male butterflies Emperor moth (Saturnia pyri) fly to females from a distance of several kilometers. If the smell of females to pass on any subject, then this subject is also starting to attract males.
The organ of perception of pheromones in insects antenna located on the head, without them, the male is unable to find a female by smell. In the antennae of males are receptors for the perception of attractants. Their sensitivity is fantastic. If the person to smell the substance of something, you need to in 1 m3 of air was at least 320 of the molecules of this substance, for butterflies, a single molecule! Male night peacock eye, which conducted experiments Fabre able to find a female smell for 8 miles!
There is a whole area of the science of the insect pheromones. Many of these substances have already been synthesized and applied in practice in pheromone glue traps. Males are attracted by the smell of a female, come to such traps and stick to them. However, to regulate the number of butterflies pests thus too expensive. Usually pheromone traps are used to determine the timing of the beginning of the summer, certain types and know when to start fighting with them in other ways.