Hard to catch: experimental evidence supports evasive mimicry

Area of Science:

• Evolutionary Biology
• Behavioral Ecology
• Predator-Prey Dynamics

Background:

• Aposematism research typically focuses on chemical defenses, neglecting signaling difficulty of capture.
• Evasive aposematism suggests that prey's evasiveness can also drive warning signal evolution, analogous to mimicry of distastefulness.
• Adelpha butterflies, known for agility and color pattern convergence, serve as a model system for studying evasive mimicry.

Purpose of the Study:

• To investigate if prey's difficulty of capture can function as an effective warning signal to predators.
• To compare predator learning and generalization between evasive and distasteful prey.
• To provide empirical evidence for the concept of evasive mimicry.

Main Methods:

• Naive blue tits were trained to associate Adelpha wing patterns with either difficulty of capture (evasive prey) or distastefulness.
• Predator avoidance learning and generalization were measured for both evasive and distasteful prey models.
• Attack rates on perfect mimics were compared between evasive and distasteful prey scenarios.

Main Results:

• Birds learned to avoid both evasive and distasteful prey wing patterns, with faster learning observed for evasive prey.
• Generalization of learned avoidance occurred for both prey types, but was broader for evasive prey.
• Perfect mimics of evasive prey experienced lower attack rates, indicating protection through generalization.

Conclusions:

• Prey's difficulty of capture can be as effective as distastefulness in deterring predators.
• Evasive mimicry, driven by predator selection against hard-to-catch prey, is supported by empirical evidence.
• Broader generalization in evasive mimicry suggests a significant role in driving color pattern convergence in species like Adelpha butterflies.