When is resemblance mimicry?

Abstract

Mimetic resemblance is extensive across the tree of life yet agreeing on what constitutes mimicry is challenging. One of the reasons for disagreement is a lack of unambiguous criteria to resolve whether a case of resemblance is a product of mimicry or alternative processes. Mimicry occurs when an organism takes advantage of the perception and association that a receiver has with a model to gain adaptive benefits. Three conditions should be fulfilled to confirm mimicry: (1) characterising a model, (2) identifying a receiver with a percept of said model and (3) demonstrating that the receiver exerts selection on the mimic. We suggest multiple lines of evidence, both experimental and correlative, to support each condition. These conditions help separate similarity due to crypsis and perceptual bias from mimetic resemblance. Furthermore, we explore forms of receiver‐mediated selection on the mimic, what mimics need to resemble for successful mimicry to occur, and the evolution of imperfect mimicry. We hope this perspective provides a functional pathway for biologists to confirm the existence of mimicry and serve as a guide for studying mimetic interactions across disciplines. A free Plain Language Summary can be found within the Supporting Information of this article.

Multimodal mimicry of hosts in a radiation of parasitic finches*

“…The similarity in the nestling phenotypes of Vidua and their respective hosts is best explained by mimicry as supposed to any other evolutionary process. Previous work has outlined a clear set of criteria for when resemblance constitutes mimicry (de Jager and Anderson 2019) as well as laying out a series of alternative hypotheses that can generate similarity (Grim 2005). Three conditions should be fulfilled to confirm mimicry: first, the model must be identified; second, the receiver must be identified; and, third, the receiver must exert selection on the mimic to converge on the model's phenotype (de Jager and Anderson 2019).…”

“…Previous work has outlined a clear set of criteria for when resemblance constitutes mimicry (de Jager and Anderson 2019) as well as laying out a series of alternative hypotheses that can generate similarity (Grim 2005). Three conditions should be fulfilled to confirm mimicry: first, the model must be identified; second, the receiver must be identified; and, third, the receiver must exert selection on the mimic to converge on the model's phenotype (de Jager and Anderson 2019). All three conditions are met in the case of Vidua : the model is the host chick, the receiver is the host parent, and previous work has shown that chicks with mismatching mouth marking are fed less, survive worse (Payne and Payne 2002; Jamie et al.…”

Natural selection in mimicry

“…While there has been occasional criticism of Haskell's () system, the foundations of employing costs and benefits remain supported and unchanged (see discussion by Bronstein, ). Measuring selection strengths and directions are ideally required to confirm the existence of mimicry (de Jager & Anderson, ), but may be difficult or time consuming. As used in Haskell's () classifications, the perceived costs and benefits of protagonists may be considered as selection surrogates when exploring the evolution of mimicry.…”

Testing for mimicry—An evolutionary biologist’s wish list

“…Several of these well-known cases of "mimicry" such as butterfly eyespots, red-black banded snakes and orchid mantises that resemble flowers are contentious. Some researchers conclude resemblance evolved via mimicry (at least in the past for some redblack banded snakes), but others instead emphasize receiver sensory bias and/or convergent evolution of the putative "models" (Bona et al, 2015;Davis Rabosky et al, 2016;Hardman et al, 2008;de Jager & Anderson, 2019;O'Hanlon et al, 2014). Conflict can also arise over definitions and semantics.…”

“…A practical method for detecting true mimics is offered in the new paper by De Jager and Anderson (), “When is resemblance mimicry?” The authors offer a step‐by‐step guide to differentiating between true mimics, who have evolved to resemble another species in response to selection imposed by a receiver, with the consequent fitness benefits, and species that just tend to look, smell or sound similar due to other factors, particularly phylogenetic constraints, convergent evolution or chance. This significantly advances the field by focussing on the biological reality of mimicry as an evolutionary process that can be tested and confirmed experimentally, rather than on developing definitions that risk becoming outdated or restrictive.…”