A hot pink insect in a rainforest sounds like a mistake. Researchers now think it may be camouflage.

Scientists have reported that the tropical katydid Arota festae can shift from bright hot pink to green in about two weeks, a change they believe helps it resemble young rainforest leaves that start out pink before turning green. The finding was published this week in the journal Ecology.

The leaf-mimicking katydid, also known as a bush cricket, is found in parts of Central and South America, including Panama, Colombia and Suriname.

The color change was spotted after researchers found an adult female at the Smithsonian Tropical Research Institute’s field station on Barro Colorado Island in Panama. When she was first seen under a light, she was hot pink. Eleven days later, she was fully green.

Researchers from the University of St Andrews, University of Reading, the Smithsonian Tropical Research Institute and the University of Amsterdam said the shift may be linked to “delayed greening.” In many tropical plants, newly emerged leaves appear in bright pink or red shades before gradually turning green as they mature.

On Barro Colorado Island, about one-third of plant species show that pattern throughout the year. The researchers said that gives a pink insect a background that can help hide it from predators.

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 color 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.”

To study the change, the researchers kept the insect in captivity for 30 days and photographed it each day. They said the vivid pink started fading after four days and became a softer pastel shade. By day 11, it matched the typical green form.

The katydid later mated and died naturally the following month.

Pink katydids have appeared in scientific literature since 1878, but they have generally been treated as rare and disadvantageous mutations. The researchers said this appears to be the first documented case of a katydid completing a full color transition within a single life stage.

Co-author Dr Matt Greenwell of the University of Reading 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 color to keep pace with the leaves it mimics shows how dynamic the rainforest can be, and is a remarkable example of camouflage in action.”

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