Diapause

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diapause

[′dī·ə‚pȯz]
(physiology)
A period of spontaneously suspended growth or development in certain insects, mites, crustaceans, and snails.

Diapause

 

a period of rest in the development of animals, characterized by a sharp decline in metabolism and a halt in formative processes. Sometimes the concept of diapause is extended to other organisms.

During diapause the organism is more resistant to unfavorable external conditions. For example, insects become resistant to insecticides. In the temperate and high latitudes the onset of diapause in many animals is determined by the length of daylight. The termination of diapause is connected with changes in the organism, which may be caused by the prolonged action of low winter temperatures. Thus, diapause ensures the animal’s ability to withstand below-freezing temperatures and hibernation. In arid subtropical and tropical climates, summer diapause, or estivation, occurs (for example, in the pink bollworm and the tomato fruitworm).

In each biological species diapause is timed to a certain phase in the life cycle. Embryonic diapause is the period of rest in the egg stage between fertilization and mitosis or toward the end of mitosis. This type of diapause occurs in rotifers, lower crustaceans, grasshoppers, Chinese silkworms, and in a number of mammals belonging to seven orders (for example, rodents and predators, including sable and mink). Larval diapause occurs, for example, in the black-veined white butterfly, which hibernates in trees during the caterpillar stage. Pupal diapause is observed among large white cabbage butterflies and cabbage moths, which hibernate in trees and in the soil during the pupal stage. Imaginal diapause occurs in such insects as mosquitoes and leaf beetles (Colorado beetles). In imaginal diapause the animal may retain its mobility, but the process of sexual maturation ceases.

V. A. SVESHNIKOV

References in periodicals archive ?
avenae, with winter emergence of juveniles and a summer-autumn diapause.
Embryo development was similar to that of other cold-water crab species, with the exceptions that 1) golden king crab did not have a diapause and 2) that the average percentage of the area occupied by the yolk at hatching, at about 40%, was much higher than that of other species.
Storage of insects can be achieved by holding them either in diapause or non diapause conditions under low temperatures (Nordlund and Morrison,
However, little is known about the physiological explanation for diapause development in this pest.
This arrested development is followed by diapause, in which development is arrested, metabolic activity is greatly reduced, and the resistance to severe physiological stress is high (Drinkwater and Crowe, 1987; Liang and Macrae, 1999).
Fitness consequences of hibernal diapauses in the pitcher-plant mosquito, Wyeomyia smithii.
These findings are consistent with hawthorn flies generally having shallower pupal diapauses and/or higher metabolic/development rates than apple flies.
Hibernation, diapauses and aestivation constitute three important adaptive responses adopted by many organisms to escape deteriorating environmental conditions.
Temperature is the most important factor which affects growth development and diapauses of Helicoverpa (Fye and Poole 1971; Attique et al.
Annual fish are unique in the fact that they develop their eggs very slowly and can go up through to three diapauses, depending on genetic and environmental factors (Myers 1952; Wourms 1972).