Does conspicuousness scale linearly with colour distance? A test using reef fish.

The colourful side of animal communication

31 May 2021

Coral reef fish learn to spot the most colourful dots displayed against a busy background.

Whether to attract a mate or ward off predators, colour signals in the animal kingdom must stand out from the surroundings. It seems reasonable to assume that the distance between two colours on the chromatic spectrum (ΔS) would affect the viewer’s ability to distinguish between them, but there have been limited behavioural studies on animals to prove this.

A team that included researchers from Deakin University in Australia trained coral reef triggerfish to peck at coloured dots and then hid the dots on a background of mixed grey-scale dots. The fish preferentially pecked the colours with the greatest ΔS from the background, but only up to a certain point, after which all highly contrasting colours proved equally conspicuous.

Understanding how animals detect and respond to colour signals will shed light on the evolution of animal communication.

Supported content

References

1. Proc. R. Soc. B 287, 20201456 (2020). doi: 10.1098/rspb.2020.1456