Evolution of switchable aposematism: insights from individual-based simulations.

Area of Science:

• Evolutionary biology
• Behavioral ecology

Background:

• Some prey animals possess aposematic signals that can be actively switched on or off.
• Switchable aposematism offers potential benefits like predator startling, enhanced learning, and reduced signal exposure.
• The cost-saving aspect of switchable aposematism, minimizing signal expense, is a key evolutionary driver.

Purpose of the Study:

• To investigate the evolutionary conditions favoring switchable aposematism over permanent signals in defended prey.
• To explore the specific environmental factors influencing the evolution of pre-attack versus post-attack switchable signals.
• To analyze the impact of predator learning speed, signal detectability, and signal costs on aposematism evolution.

Main Methods:

• An individual-based computer simulation model was developed to simulate predator-prey interactions.
• The model incorporated parameters such as predator learning speed, prey signal detectability, signal cost, and switching cost.
• 88,128 model runs were conducted to observe the evolutionary outcomes of different aposematic strategies.

Main Results:

• Pre-attack switchable aposematism generally evolves under moderate predator learning, high basal detectability, and moderate to high signal costs.
• Post-attack signals tend to evolve with slow predator learning, low basal detectability, and high signal costs.
• Fast predator population turnover can favor post-attack signals that deviate from typical evolutionary tendencies.

Conclusions:

• Switchable aposematism's evolution is contingent on predator learning dynamics, signal characteristics, and environmental factors.
• The study provides the first theoretical framework for systematically comparing switchable and permanent aposematism.
• The simulation software and data are publicly available for further research into aposematic signal evolution.