From Big Medical Encyclopedia

POLYPHAGIA (polyphagia; it is a lot of + phagein to eat, devour Greek poly; synonym mnogoyadeniye) — overconsumption of food — see. Bulimia .

The POLYPHAGIA in biology

the POLYPHAGIA in biology (grech, there is a lot of + phagein to eat, devour poly) — polyphagia; ability of animals to eat various food of plant and animal origin. Items usually oppose monophagisms (see) and stenofagiya — to specialized food the few, types of food usually close in character. The concept «pantophagia», or «evrifagiya» (pantophagy), reflects the property inherent in rather small circle of animal species; it is wider than the concept «polyphagia».

Distinguish from polyphagues the phytopolyphagues (caterpillars and a number of butterflies, voles, etc.) feeding on the most various vegetable food and the zoopolyphagues (coelenterates, many predatory insects and mammals) feeding on various animal food.

The item represents important biol, adaptation giving to animals the chance to survive in places with limited and non-constant stocks of separate types of food i.e. promotes survival of a look and its expansion area (see). Animals polyphagues generally live in moderate and high latitudes; in their tropics it is much less since the tropical zone is characterized by rich and various caches. Macrothermophiluses eat one or several types of food more often.

The item meets almost in all groups of animals. The exception is made parasites (see), (endoparasites) which are especially living in bodies, fabrics and perigastriums of an animal. At P.'s ectoparasites it is observed more often. The number of the types of food used by this or that species of animals can reach at polyphagues of several honeycombs. So, the ordinary vole can eat more than 400 types of food, a gray hamster — more than 200 types. The food consumed by martens and sables half consists of forages of a plant origin (nuts, berries, fruits) and half — of animal forages. Polyphagues are the majority of insects (butterflies, bugs) though many of them and stenofag. Among birds the expressed polyphagues are some vranovy birds, first of all crows, rooks and daws.

By the item it is closely connected with mechanisms of transfer of causative agents of various diseases of the person and animals (see. Mechanism of transmission of infection ), especially in the natural centers of diseases. Distribution in populations of rodents of an epizooty of plague and transition of activators just seeing to another is directly connected with P. of many types of carriers of plague — the fleas attacking several types of owners. Larvae and the nymphs of ixodic mites parasitizing on birds and mammal different types promote spread of such diseases as a tularemia, a tick-borne typhinia, etc., an epizooty of a tularemia among many species of rodents, insectivorous and predators.

Polyphagues, though can eat different types of food, but, as a rule, give preference only a nek-eye from them (the main forages), and the choice depends on a season, age and fiziol, conditions of animals. Such way of food provides the normal growth and development of an animal, guarantees intensive reproduction of polyphagues. Transition to the replacing, surrogativny forages («food on need») sometimes is followed by an aggravation of symptoms of polyphagues and the termination of their reproduction. Such replacing forages allow to support existence, but do not provide reproduction of animals.

Bibliography: Naumov N. P. Zooecology, M., 1963.

N. P. Naumov.