Green insect turns a puzzling shade of hot pink
In total darkness around midnight last March on Panama’s Barro Colorado Island, a team of scientists made a surprising discovery: a bright pink katydid hiding leaves (Arota Festivals), striking a pose in the glow of the light of a research station.
Leaf-masking katydids are camouflage insects that typically look like green leaves to ward off predators. Roses are rare among rainforest-dwelling species, so researchers kept the adult female bug under observation. Eleven days later, it was green.
Researchers say this is the first time a katydid has been observed making a complete color change during a single stage of its adult life. Previously, scientists considered pink katydids to be rare and disadvantageous mutants. The team that discovered this color-changing insect believes its transformation from bright pink to green could have evolved to mimic “delayed greening” in rainforests, which occurs when budding tropical leaves turn from pink or red to green. The results are described in a study recently published in the journal Ecology.
“Rather than a genetic quirk, this may actually be a fine-tuned survival strategy that follows the life cycle of the leaves of the rainforest that this insect is trying to resemble,” Benito Wainwright, a biologist at the University of St Andrews in Scotland and lead author of the study, said in a press release.
For 30 days, the research team observed the bright pink insect at natural ambient temperatures and humidity. By the fourth day, the insect’s bright pink body had turned pastel pink. By day 11, it was indistinguishable from the standard green version.
The scientists also examined whether the vibrant coloring could act as a deterrent to predators, such as birds, bats and frogs, reducing the risk of attack. Further study of these bright pink katydids, including experiments allowing the team to determine whether the insects use the pink coloration for camouflage or as warning signals, could help explain why they change color.
“You would think that a bright pink insect in a mostly green forest would stand out from predators, like a worker wearing a high-visibility jacket,” added Matt Greenwell, co-author and researcher at the University of Reading. “The idea that an insect can gradually change color to follow the rhythm of the leaves it imitates shows how dynamic the rainforest can be and is a remarkable example of camouflage in action.”
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