Abstract
Biologists usually pursue the adaptationist paradigm in trying to explain the functional significance of animal coloration. Here I collate instances in which coloration may be a poor match in the context of background matching, Batesian mimicry, aposematism, and colour polymorphisms. This can occur because of trade-offs with other functions, relaxed selection from predation, or colour trait neutrality. Also, mechanistic, pleiotropic and chance genetic effects can all result in a poor match to the background environment or to signaling efficiently. While biologists implicitly recognise these constraints placed on adaptive coloration, they rarely explicitly acknowledge the heterodox notion that coloration might be under weak selection or no selection at all. Unfortunately, it is difficult to show this definitively, as illustrated in an investigation into the function of colour polymorphisms in coconut crabs.
Highlights
For a century and a half biologists have been trying to understand the adaptive significance of animals’ external appearances
I point to genetic phenomena that result in external appearances ill-suited to signaling and protective coloration
Demonstrating that coloration has no immediate adaptive value is a serious challenge, and I highlight this difficulty using an example of colour polymorphism in coconut crabs (Birgus latro)
Summary
For a century and a half biologists have been trying to understand the adaptive significance of animals’ external appearances. Keywords Background matching · Coconut crabs · Imperfect mimicry · Non-adaptive · Pleiotropy · Relaxed predation · Trade-offs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
