Aestivation

Definition

A period of summer dormancy characterized by metabolic depression and behavioral inactivity, entered in response to high temperatures, aridity, or other unfavorable seasonal conditions. In arthropods, aestivation enables survival during hot, dry periods when foraging, reproduction, or development would be physiologically costly or impossible. The state is terminated when favorable moisture or temperature returns, often triggered by rainfall or cooling.

Etymology

From Latin aestivare, to spend the summer, from aestas, summer

Example

The desert locust Schistocerca gregaria may aestivate as a nymph or adult during extreme heat, burrowing into sandy soil to reduce water loss and metabolic demand until monsoon rains trigger resumption of activity and reproduction.

Synonyms

• estivation
• summer dormancy

Related Terms

• Diapause
• hibernation
• brumation
• Cryptobiosis
• anhydrobiosis
• Quiescence
• dormancy

Usage Notes

Aestivation contrasts with hibernation (winter dormancy) and diapause (a hormonally programmed, often seasonally anticipatory arrest that may occur in any season). Unlike diapause, aestivation is typically a direct response to immediate environmental stress rather than a genetically fixed developmental program, though the distinction can blur in some species. The spelling 'estivation' is an accepted variant in American English; 'aestivation' predominates in British and scientific usage. Some specialists reserve 'aestivation' for drought-driven dormancy and avoid applying it to simple heat avoidance, preferring 'summer quiescence' for the latter.