Batesian mimicry

Definition

A form of defensive mimicry in which a palatable, harmless species (the mimic) evolves a resemblance to an unpalatable, defended, or dangerous species (the model), thereby gaining protection from predators that have learned or evolved to avoid the model based on its warning signals. The effectiveness of Batesian mimicry depends on the relative frequency of models and mimics: mimics are protected only when predators encounter models often enough to maintain aversive learning, but encounter mimics rarely enough that the association between warning signal and unpleasant experience remains strong. The term contrasts with Müllerian mimicry, in which multiple unpalatable species share similar warning signals.

Etymology

Named for Henry Walter Bates (1825–1892), the English naturalist who first described the phenomenon in 1861 based on his studies of Amazonian butterflies.

Example

The drone fly (Eristalis tenax), a harmless syrphid fly, exhibits Batesian mimicry of the honey bee (Apis mellifera), sharing similar yellow-and-black banding that deters predators familiar with bee stings.

Related Terms

• Müllerian mimicry
• mimicry
• aposematism
• warning coloration
• automimicry
• frequency-dependent selection

Usage Notes

The distinction between Batesian and Müllerian mimicry can be blurred when a species' palatability varies geographically or when multiple species with differing defenses share signals (quasi-Batesian or quasi-Müllerian systems). Specialists reserve 'Batesian' strictly for cases where the mimic is palatable and the model is genuinely defended; the term should not be used for cases where both species are unpalatable, which is Müllerian mimicry.