Evolution of temperature preference behaviour among Drosophila larvae.

Area of Science:

• Evolutionary Biology
• Animal Behavior
• Physiology

Background:

• Small-bodied ectotherms are sensitive to temperature fluctuations, relying on thermotaxis for survival.
• Understanding the evolution of thermotactic behaviors is crucial for predicting species' responses to climate change.
• Drosophila melanogaster is a model organism for studying temperature sensing, but its evolutionary context is less understood.

Purpose of the Study:

• To investigate the evolutionary patterns of thermotactic behaviors in eight *Drosophila* species.
• To identify the mechanisms driving differences in thermal preference among species.
• To assess the role of local adaptation in shaping temperature-related behaviors.

Main Methods:

• Thermo-profiling of over 2400 larvae across eight *Drosophila* species.
• Comparative analysis of temperature preference and navigational behaviors.
• Agent-based modeling of larval thermotaxis circuits.

Main Results:

• Significant variation in temperature preference and navigation was observed among species, consistent with local adaptation.
• Differences in thermal preference are primarily driven by the balance between cool and warm avoidance circuits.
• Temperature sensitivity itself showed less variation compared to avoidance circuit dynamics.

Conclusions:

• Thermotactic behaviors evolve recurrently in *Drosophila* species inhabiting diverse thermal environments.
• The evolution of avoidance circuit balance, not just sensitivity, shapes thermal niche adaptation.
• This cross-species system provides a tractable model for studying the evolution of temperature-related behaviors.