If a movie producer were casting a sea creature for appeal, the bumblebee shrimp would certainly make the cut. Dressed to impress, the pea-sized crustacean sports an eye-catching outfit of yellow and black bumblebee stripes, accentuated with a pair of goggley blue eyes and a wispy fan of a translucent tail — the epitome of cute.
Bumblebee shrimp inhabit tropical Pacific and Caribbean waters, living in a symbiotic relationship with echinoderms, including sea stars, sea cucumbers and sea urchins. In Indonesia they are most frequently seen scurrying across the backs of slow-moving, sausage-shaped sea cucumbers; in the Caribbean we primarily find then associated with sea urchins and, occasionally, sea stars. Whenever they appear, the charismatic critters’ star quality always stops us in our tracks. Only recently we found out that our loveable little shrimp has a dark side to its nature.
Symbiosis — the state of two organisms living in close association — has several categories, which are not always clear-cut in definition. In mutualism, two life forms live together in a relationship beneficial to both. In the instance of commensalism, one partner prospers from the association, while the other neither profits nor is harmed. Then there is parasitism, which brings us back to our whimsical little bumblebee shrimp, which just happens to hang around its hosts in order to dine on their tiny tube feet. Fortunately, tube feet — a hallmark of the echinoderm phylum — are numerous, numbering in the hundreds, and a few nips here or there will do little to slow the shrimps’ lumbering meal tickets.