Understanding Mimicry – with Special Reference to Vocal Mimicry

Abstract The term mimicry was introduced to biology in 1862 by H enry W alter B ates in his evolutionary explanation of deceptive communication in nature, based on a three‐part interaction system of a mimicked organism or object (called model), a mimicking organism (called mimic), and one or more organisms as selecting agents. Bates gave two incongruous definitions of mimicry: one from the viewpoint of a natural agent that selects for, and in consequence is deceived by, the close resemblance of a toxic model's warning signal and the similar appearance of a palatable mimic, and another one from the viewpoint of a human taxonomist who under an evolutionary aspect focuses on convergent resemblance between model and mimic. Later definitions of Müllerian ( F . M üller), arithmetic ( A . W allace) and social ( M . M oynihan) mimicry abolish deception in the natural selecting agent, rely on the convergence criterion alone, fuse the roles of model and mimic but have to accept a mix of homologous and convergent resemblance amongst them for a functional explanation. The definition of vocal mimicry ( E . A rmstrong) refers to a learned resemblance between mimic and heterospecific model by character duplication (no convergence), so far without known (deceived or not deceived) natural selecting agents. It excludes B atesian vocal mimicry. The functional ethological understanding of mimicry as a tripartite communication system ( W . W ickler) is consistent with Bates' concept and accepts deception as key element of Batesian mimicry beyond homologous and convergent resemblances. Deception is seen as caused by the divergence between a sign and its meaning for the natural selecting agent. This understanding covers mimicry in all behaviour domains, provides a generally applicable definition of mimic and model so far missing in any mimicry concept, and it distinguishes – still in line with Henry Bates – cultural from genetically determined model‐mimic‐resemblance; this applies to vocal mimicry in particular. Convergently evolved model‐mimic‐resemblance, not essential in B atesian mimicry but mandatory for its alternatives, marks a fundamental distinction between B atesian mimicry (including M imesis) and all other conceptualized mimicries and accounts for the non‐existence of a unified meaning of the term mimicry. However, character convergence does not help to explain the mere existence of mimicry phenomena and is irrelevant for their permanence in nature. I therefore propose to remove the convergence argument from any mimicry definition.