A tropical insect has been found to change colour from vivid hot pink to green within a fortnight, which scientists believe may mimic the young leaves of rainforest plants.
The findings, published this week in the journal Ecology , focuses on arota festae, a leaf-masquerading katydid also known as a "bush cricket", native to Panama, Colombia and Suriname.
When researchers spotted an adult female beneath a light at the Smithsonian Tropical Research Institute's field station on Barro Colorado Island, Panama, she was an unmistakeable hot pink. Eleven days later, she was completely green.
Scientists from the University of St Andrews, University of Reading, the Smithsonian Tropical Research Institute, and University of Amsterdam, propose that the pink colouration evolved to mimic "delayed greening", a phenomenon in which newly emerged tropical leaves flush vivid shades of pink or red before maturing to green.
On Barro Colorado Island, around one-third of plant species show this trait all year, providing a reliable supply of pink leaves for a camouflaged insect to blend into.
Lead author Dr Benito Wainwright, of the University of St Andrews, said: "Finding this individual was a genuine surprise. Because it was so rare, we kept it in natural conditions and found it changing colour from hot pink to green.
"Rather than a bizarre genetic quirk, this may actually be a finely tuned survival strategy that tracks the life cycle of the rainforest leaves this insect is trying to resemble."
The team reared the individual in captivity for 30 days, photographing her daily. The hot pink faded to pastel after four days, and by day eleven, she was indistinguishable from the common green morph.
She survived to mate before dying naturally the following month.
Pink katydids have been documented in scientific literature since 1878 but were generally considered a rare, disadvantageous mutation. This appears to be the first recorded case of a katydid completing a full colour shift within a single life stage.
Dr Matt Greenwell, of the University of Reading, a co-author of the study, said: "Tropical forests are extraordinarily complex environments, and this discovery hints at just how precisely some animals have evolved to exploit them.
"You would think that a bright pink insect in a mostly green forest would stand out to predators like a worker in a high-vis jacket. The idea that an insect might gradually shift colour to keep pace with the leaves it mimics shows how dynamic the rainforest can be, and is a remarkable example of camouflage in action."
