Land crab migration

Aquatic scientific names in the news …

3rd May 2017

Land crab migration

It’s that time of the year when land crab migrations tend to be in the news. The most recent reports are on the migration of red, yellow, and black land crabs in Cuba marching from the inland forests down to the sea at the Bay of Pigs. The species of land crabs involved in the Cuban migration is Gecarcinus ruricola.

Image: P.Lindgren

After the first spring rains millions of female crabs migrate to the sea to spawn before returning to their burrows in the forests. In around 20 days the reverse will happen with millions of crab larvae emerging from the sea and migrating to the forests to spend the rest of their lives on land.

Image: Jonathan Wilkins

The land crab breeding migration is an annual event but varies in timing and intensity from year to year. It usually starts anytime from mid April to mid May and can last for up to 3 months, sometimes with a peak in mid May, sometimes with no obvious peak in activity. The migrations show some correlation with moon phase but are more strongly influenced by rainfall, though not in any consistent way.


Etymology



Gecarcinus ruricola (Linnaeus, 1758) variously called the Purple Land Crab, Black Land Crab, or Red Land Crab

Gecarcinus – Greek, Ge-, gh (γη), earth, ground, land; carcinus, karkinos (καρκινος), crab.
ruricola – Latin, that lives in or belongs to the country, rural, rustic.

Note: the proliferation of common names owes to the existence of numerous colour morphs of this species including black, red, yellow, and green.

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