A quantitative model of temperature-dependent diapause progression

Area of Science:

• Insect physiology
• Developmental biology
• Ecology

Background:

• Winter diapause in insects is crucial for survival, preventing development before spring.
• Quantitative understanding of diapause termination's temperature dependence is limited.
• Diapause phenotypes are often cryptic, hindering study.

Purpose of the Study:

• To develop a methodology for quantitatively assessing temperature-dependent diapause termination.
• To characterize the thermal reaction norm for diapause termination in Pieris napi.
• To investigate the relationship between diapause termination and postdiapause development rates.

Main Methods:

• Butterfly pupae (Pieris napi) were moved from various cold conditions to 20 °C.
• Diapause termination timing was recorded to determine temperature-dependent rates.
• Postdiapause development rates were measured across a range of temperatures.

Main Results:

• Diapause termination in Pieris napi follows a temperature-dependent rate process, peaking at cold temperatures.
• A thermal reaction norm was established, predicting diapause termination under variable temperatures.
• Postdiapause development exhibits a distinct thermal performance curve, optimal around 31 °C.

Conclusions:

• Diapause termination and postdiapause development are distinct, temperature-dependent processes.
• The interplay of these processes ensures synchronous spring eclosion in Pieris napi.
• This quantitative model enhances understanding of diapause as an adaptation for survival and synchrony.