Happy new start of „Take a Minute to Relax“ in 2021 with some visual meditation: Meet the harlequin shrimp (hymenocera elegans).
Origin of Harlequin Shrimp (Hymenocera elegans)
In this first minute of relaxation of the new year, we’d like to focus your attention on this gorgeous, but voracious little hunter. A juvenile Harlequin Shrimp. There are two types of harlequin shrimp: hymenocera elegans is native to the Indo-Pacific region and hymenocera picta which is specific to Hawaii. The name of the genus Hymenocera is derived from the Greek words “hymen” (membrane) and “keras” (horn, or in this case antennae), indicating that this crustacean has lamina-shaped antennae. Whereas both “elegans”, as well as “picta” refer to the beautiful coloured spots adorning the exoskeleton of this decapod.
Where harlequin shrimps live
They are reef dwellers, preferring water temperatures of 24-29 degrees Celcius, and are especially partial to a habitat with spaces for them to retreat into, like branched corals or rock formations. Their eyes are positioned on stalks, and they have two giant flat claws that serve as snipping tools while harvesting their prey. Females are generally larger than males and can grow up to around 5cm.
How hymenocera elegans looks
Harlequin shrimp are white to light pink in colour, with splashes of bright coloured spots on their entire body, usually red, purple, orange, and blue. Despite their relatively small size, they have few natural predators. This is thanks to their markings and colouration. Like on land, in the ocean bright patterns are a red flag to predators of toxicity. In addition, their colouration serves as a wonderful camouflage when moving along a coral reef, mimicking the bright lights and shadows produced by the overhead sun.
What and how harlequin shrimps eat
What’s curious about the Hymenocera is that they live almost exclusively on a diet of sea stars. Some have been observed munching on sea urchins, but generally speaking, sea stars are their comfort food. The harlequin shrimp has two flat antennae that are used for detecting the scent of sea star prey. They will often hunt as mating pairs, and work together to overtake and devour their prey. One shrimp will use its claws to clip the soft tube feet attaching the sea star to its surface, while the other then pulls the creature away from the surface and onto its back.
Some harlequin shrimp will then drag the sea star to its lair, and feed on its tube feet and soft tissues. Unable to right itself, the starfish will then endure being eaten alive for a period of days to weeks, depending on the size of the starfish. Harlequin shrimp have been observed feeding the starfish to keep it alive for their consumption.
How hymenocera elegans reproduces
Harlequin shrimp mate for life, and are fiercely protective of their family territory. Once the pair finds a suitable home within the reef, they are known to stay within the area for months or even years. The pair mate after the female moulds, and can produce anywhere from 100 to 5,000 eggs per breeding season. This may seem like a lot of offspring, but the high demand for harlequin shrimp in the aquarium trade has made them rarer in the wild.
What makes harlequin shrimps special (apart from their look)
Since Hymenocera has a symbiotic relation with corals, this isn’t exactly good news for coral reefs! Hymenocera preys on sea stars that would otherwise eat the corals, and in return for its efforts, it gets a safe place to live. Without the help of these little creatures, the future of the reef as a whole is at risk.
There is more
Have a happy and healthy new year!