Regulation of Diapause

A synthesis of what triggers, maintains and ends diapause in insects — the sensitive stage, the photoperiodic and thermal cues, the hormonal control, and the chilling requirement that must be satisfied before development can resume.

Studied in

Insecta

Sample size

review of diapause regulation across insect groups

Diapause is a programmed developmental arrest initiated in advance of adverse conditions, not a response to them. It is cued at a species-specific sensitive stage, often generations before the arrest itself, is hormonally maintained, and typically requires a period of chilling before it can be terminated — so an insect in diapause cannot be woken by a warm spell.

• Regulation differs substantially between diapause stages and between species.
• The endocrine account is best characterised in a handful of laboratory species.
• Field validation of chilling requirements is patchy.

• Seasonal survival

  Animals commit to winter before winter arrives, using day length rather than weather

• Seasonal survival

  An insect in diapause usually has to be cold for weeks before warmth can restart it

• Diapause

  Diapause is a prediction, not a reaction. It is triggered by daylength before conditions worsen — sometimes a generation ahead — and an insect in diapause moved somewhere warm and well-fed simply stays in diapause.

• Diapause

  A motionless insect in the cold is usually not in diapause. Quiescence — a direct response to bad conditions that reverses as soon as they improve — is commoner, and looks identical from outside.