Toggle Main Menu Toggle Search

Open Access padlockePrints

Variable crab camouflage patterns defeat search image formation

Lookup NU author(s): Dr Jolian Troscianko, Dr John Skelhorn



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Understanding what maintains the broad spectrum of variation in animal phenotypes and how this influences survival is a key question in biology. Frequency dependent selection – where predators temporarily focus on one morph at the expense of others by forming a “search image” – can help explain this phenomenon. However, past work has never tested real prey colour patterns, and rarely considered the role of different types of camouflage. Using a novel citizen science computer experiment that presented crab “prey” to humans against natural backgrounds in specific sequences, we were able to test a range of key hypotheses concerning the interactions between predator learning, camouflage and morph. As predicted, switching between morphs did hinder detection, and this effect was most pronounced when crabs had “disruptive” markings that were more effective at destroying the body outline. To our knowledge, this is the first evidence for variability in natural colour patterns hindering search image formation in predators, and as such presents a mechanism that facilitates phenotypic diversity in nature.

Publication metadata

Author(s): Troscianko J, Nokelainen O, Skelhorn J, Stevens M

Publication type: Article

Publication status: Published

Journal: Communications Biology

Year: 2021

Volume: 4

Print publication date: 05/03/2021

Online publication date: 05/03/2021

Acceptance date: 04/02/2021

Date deposited: 07/03/2021

ISSN (electronic): 2399-3642

Publisher: Nature Publishing Group


DOI: 10.1038/s42003-021-01817-8


Altmetrics provided by Altmetric


Funder referenceFunder name
funded by a BBSRC grant BB/L017709/1 to M.S. and J.S.
NERC Fellowship NE/P018084/1 to J.T.