Citation: Stevens, M., P. R. Cheo & P. A. Todd, 2013. Colour change and camouflage in the horned ghost crab Ocypode ceratophthalmus. Biological Journal of the Linnean Society. doi: 10.1111/bij.12039
A paper published in the Biological Journal of the Linnean Society about ghost crab camouflage arose from a collaboration between Martin Stevens, Peter Todd and his hons student Cheo Pei Rong. BBC Nature News picked up the story on 5th April 2013:
This was picked up by WildSingapore when it first came out .and circulated in the local naturalists community. To find out more about this crab on our shores, Wild Singapore which has a page on Ocypode ceratophthalmus here.
Abstract – Species that change colour present an ideal opportunity to study the control and tuning of camouflage with regards to the background. However, most research on colour-pattern change and camouflage has been undertaken with species that rapidly alter appearance (in seconds), despite the fact that most species change appearance over longer time periods (e.g. minutes, hours, or days).
We investigated whether individuals of the horned ghost crab (Ocypode ceratophthalmus) from Singapore can change colour, when this occurs, and how it influences camouflage.
Individuals showed a clear daily rhythm of colour change, becoming lighter during the day and darker at night, and this significantly improved their camouflage to the sand substrate upon which they live. Individuals did not change colour when put into dark conditions, but they did become brighter when placed on a white versus a black substrate.
Our findings show that ghost crabs have a circadian rhythm of colour change mediating camouflage, which is fine-tuned by adaptation to the background brightness. These types of colour change can enable individuals to achieve effective camouflage under a range of environmental conditions, substrates, and time periods, and may be widespread in other species.