A simple and dynamic thermal gradient device for measuring thermal performance in small ectotherms.

Area of Science:

• Physiology
• Ecology
• Bioengineering

Background:

• Ectothermic animals' body temperature is highly sensitive to environmental conditions, directly influencing their fitness and performance.
• Understanding thermal performance requires controlled laboratory experiments, but creating multiple simultaneous thermal environments is often costly and complex.
• Small ectotherms, such as insects, are ideal models, but experimental setups can be limiting.

Purpose of the Study:

• To introduce a novel, cost-effective thermal gradient device for creating a wide range of temperatures simultaneously in a laboratory setting.
• To demonstrate the device's utility for static and dynamic thermal experiments with ectotherms.
• To facilitate large-scale assessments of organismal thermal performance, survival, and behavior.

Main Methods:

• Construction of a thermal gradient device using an aluminum plate, copper piping, and refrigerated circulators.
• The system is designed to operate across a broad temperature range (e.g., -6°C to 40°C).
• Proof-of-concept experiments included generating a low-temperature survival curve for *Drosophila melanogaster* and assessing cricket (*Gryllodes sigillatus*) growth under fluctuating thermal cycles.

Main Results:

• The device successfully generated a range of temperatures, enabling the creation of a low-temperature survival curve for flies.
• The system allowed for the exploration of daily thermal cycles' effects on cricket growth rates.
• The approach proved effective in avoiding the need for multiple incubators or baths.

Conclusions:

• The developed thermal gradient device offers a simpler, faster, and more economical solution for conducting thermal performance and survival experiments.
• This innovation supports diverse applications, including thermal performance curves, response to fluctuating temperatures, and behavioral studies across temperature gradients.
• The device enhances the feasibility of large-scale ectotherm research under controlled thermal conditions.