In 2020, scientists found sparkling Peinaleopolynoe on hydothermal vents in the eastern Pacific – and were irresistibly reminded of the king of rock’n’roll
The worms’ colours are created not by pigments but by light reflecting and refracting within the internal structure of the scales, in the same way as with shining blue butterfly wings. The only light available in the deep sea to make them sparkle is the bioluminescence of other animals, but they gleam brilliantly in the headlights of deep-diving robots and submersibles.
It’s possible that as worms get older their colour changes because their scales grow thicker, altering how light passes through them. The thickest scales are blue. Slightly thinner are pink. “The littlest worms tend to always be white and the scales are very flimsy,” says Hiley.
Hungry scale-worms bounce on the spot and throw punches at each other, inverting their snout and biting chunks out of each other with their powerful jaws. “It was a piece of the puzzle that we didn’t know for a long time,” says Hiley. It is still not clear why the worms fight each other. “We have more observation to do, definitely,” she says.One more puzzle that Hiley wants to solve is how hungry scale-worms evolved from ancestors living in shallow seas to be able to survive in the low-oxygen, hyper-pressurised environment of the deep sea. She is looking for clues in their genes.
“We are starting to see some weird things on a genetic level with these deep-sea worms,” says Hiley. The 29 species of deep-sea scale-worms, including the hungry species, have a huge variation in their gene order compared with species of worms that live in shallow seas. Hiley is investigating whether this may somehow help explain how the worms have adapted to the rigours of the deep ocean.