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A woodlouse underwater. Photo Credit: Martin Stjernstedt |
Artificial night-time light confuses a color-changing coastal woodlouse, new research shows.
The sea slater is an inch-long woodlouse that lives around the high-tide line and is common in the UK and Europe.
Sea slaters forage at night and can change color to blend in and conceal themselves from predators.
The new study, by the University of Exeter, tested the effects of a single-point light source (which casts clear shadows) and “diffuse” light (similar to “skyglow” found near towns and cities).
While the single light did not interfere with the sea slaters’ camouflage, diffuse light caused them to turn paler while hiding on a dark background – making them more visible.
“With night skies getting brighter worldwide, it’s important to understand how this will affect the natural world,” said Kathryn Bullough, who led the study as part of her masters at the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.
“We know artificial light causes all sorts of negative effects for animals and plants, but our results show that shadow-casting light can have very different impacts to diffuse skyglow, even when both have the same overall brightness.