Modeling the costs and benefits associated with the evolution of endothermy using a robotic python

Area of Science:

• Evolutionary Biology
• Physiological Ecology
• Thermoregulation

Background:

• Endothermy offers advantages but demands high energy, making its evolutionary path complex.
• Studying intermediate steps between ectothermy and endothermy is crucial for understanding evolution.
• Brooding pythons exhibit facultative endothermy, providing a model for non-essential endothermy.

Purpose of the Study:

• To determine the energetic costs of maintaining a clutch at a preferred temperature using a controllable artificial snake.
• To assess the thermal benefits of partial energy investment (50% of required energy) for incubation.
• To investigate the influence of clutch size, diel ambient temperature cycles, and insulation on energy requirements and thermal quality.

Main Methods:

• An artificial snake with controllable heating was used to simulate incubation.
• Experiments manipulated clutch size (5, 10, 15 eggs), diel ambient temperature cycles (2, 4, 6°C), and insulation (present/absent).
• Three power levels were tested: unlimited, 50% required, and no power.

Main Results:

• Clutch size did not significantly affect power requirements or developmental temperature.
• Energy requirements increased with greater diel temperature fluctuations and decreased with insulation.
• Thermal environment quality decreased with increased diel temperature amplitude and with the addition of insulation.

Conclusions:

• Environmental conditions, particularly temperature variability and insulation, play a significant role in the energetic costs of endothermy.
• The study provides insights into the trade-offs associated with energy investment in reproduction and thermoregulation.
• Findings contribute to models on the evolution of endothermy, highlighting the importance of intermediate strategies.