ASK THE EXPERT?
Harlequin shrimp Hymenocera picta
One of the most well known, yet difficult to find shrimps, this species forms pair bond relationships in which the female is the largest and most dominant. They live on rocky reefs and coral reefs in areas of good water movement. In many cases they have a lair beneath a rock or in a coral labyrinth where they live. The pair hunt together generally feeding on smaller Sea Stars which they can narcotise and drag back to their lair to feed on in safety.
Of course, they will also feed on larger sea stars if the stars range into their territory but this is more incidental feeding, as the large sea stars can crawl away when they are attacked.
Harlequin Shrimps have a unique way of feeding. On the smaller Sea Stars they eat from the end of the arm up to the disc and then begin on another arm. I have seen no cases in the wild where they actually kill their prey, or eat it entirely.
The result of this is that the Sea Star gets away and is able to regenerate its legs. In fact, this very practice makes it easy for observant divers to recognise which species of sea stars are missing arms and conclude that there are harlequin shrimps nearby.
Female Pacific Ocean harlequin shrimp Hymenocera picta. Females have shawl-like skin flaps along their sides to protect the eggs when they are laid beneath the abdomen. (Loloata Island, Papua New Guinea).
(Photo Neville Coleman)
One of the first photographic records of Harlequin Shrimp Hymenocera picta behaviour in Australia was taken at Warroora on the central Australian westcoast during July 1972. This Indian Ocean Harlequin Shrimp has a blue coloration. It has been feeding on the arms of the sea star Nardoa sp.
(Photo Neville Coleman)
Indian Ocean colour form of the Harlequin Shrimp Hymenocera picta.
(Photo Neville Coleman)