Sex Hormone in Crabs' Eyes Produces Body Parts Essential for Reproduction

Female blue crab's eyes play a role in growing body parts that enable the crabs to mate and reproduce, according to researchers at the University of Maryland's Institute of Marine and Environmental Technology (IMET).

It has been known that the crabs' eyeballs produce hormones responsible for the growth and development for a crab from adolescence to adulthood, but this new find is noteworthy for its necessity in crab motherhood.

"This is the first definitive evidence for the presence of a female-specific hormone in crabs that regulates the development of structures essential for mating and caring for their eggs," said author J. Sook Chung, an associate professor with the University of Maryland Center for Environmental Science. "This hormone is required for maternal care."

A sex hormone known as CSFH is vital to female blue crabs (Calinectes sapidus) is vital to the maturation of the crab, Chung and his colleagues learned.

"For the first time in crustaceans, a substance that is critically involved in the control of expression of relevant adult anatomic features in females has been identified," said IMET director Russell Hill. "This is very significant basic research on a molecular level that also may have practical application in the future, as with most of the important research at IMET."

The role of CSFH in female crabs' maturation is a vital one, as the crustaceans only mate once in their lives, at the very moment they molt for the final time and reach maturity. The sex hormone triggers the development of a special pouch that stores the sperm of a male crabs. After the crabs mate, the sperm stays in these receptacles for up to two years. The female crab will use the sperm intermittently to fertilize eggs.

The CSFH hormone also triggers the development of external structures that hold fertilized eggs on the outside of the crabs body, the researchers learned.

A paper detailing their research is featured in the journal Endocrinology.