The Elements of Evolution (46-6) Marbled Crayfish

Marbled Crayfish

The marbled crayfish (aka marmokreb) is a 4–8 cm freshwater decapod discovered in the pet trade in Germany in the late 1990s. (Marmokreb is German for “marbled crayfish.” They are one of the most popular crayfish in the international pet trade.) 10-legged decapods are the crustacean order of crayfish, crabs, lobsters, prawns, and shrimp.

The marmokreb is parthenogenetic: the only decapod known to reproduce without sex. Their being uniquely triploid – having 3 chromosome sets – may be the reason. All marbled crayfish are female clones, and they lay lots of eggs.

Only 1 in 10,000 animals species comprise cloning females. Many studies suggest that parthenogens are rare because they don’t last long. Lacking genetic diversity, a single disease might readily wipe out a population.

Marmokrebs are obviously creatures of saltation. Their DNA indicates that they arose 1,250 years ago, but they were never seen before the late 20th century.

Having been set loose in lakes and streams by pet owners, marmokrebs have gone invasively wild, merrily walking hundreds of meters to reach new water sources. Feral populations have been spotted throughout eastern Europe (north and south), in Madagascar, and in Japan. Marmokrebs have been able to thrive in a variety of habitats with just their single genome.

Asexuality is a fantastic short-term strategy. ~ American biologist Abraham Tucker