The pea crab, Pinnotheres pisum, is a small crab in the family Pinnotheridae that lives as a parasite in , , , and other species of .
Etymology
Pinnotheres is
Greek language for "guard of
Pinna" and
pisum is
Latin for a
pea, in reference to the shape of the crab.
Description
Pea crabs are small crustaceans about the size of a pea or dime, with a "smooth dorsal surface of the carapace, or upper exoskeleton".
The
exoskeleton of males is hard and circular and has eyes and antennae extending from their fronts, and the
are more robust in males than in females, which have more elongated chelipeds.
The bodies of the female pea crabs are often
translucency and show the inner organs and gonads as yellow and red, with the males being a "more yellowish-grey with patches of brown".
Ecology
The relationship between the pea crab and its host is one of
parasitism, rather than
commensalism, since the host may be harmed by the crab's feeding activities.
The pea crab relies solely on its host for food, safety, and oxygen.
Pea crabs have a variety of hosts, the most important of which are mollusca. The pea crab lives in the mantle cavity of these hosts.
Little is known about the pea crab's feeding habits,
Mating
A male pea crab will rub the edge of a shellfish containing a female pea crab for hours until the shellfish opens and allows the male pea crab to enter.
[ Nationalgeographic.com 2015-05-08 Crab Tickles Shellfish for Hours to Find Love]
A study by New Zealand researchers Oliver Trottier and Andrew Jeffs from the University of Auckland shows this behaviour in a similar parasitic pea crab, Nepinnotheres novaezelandiae.[ ]
See also
