Antarctic molluscs can 'switch sex'

Researchers from the National Oceanography Centre, Southampton have discovered the hermaphrodite nature of Antartic bivalves known as Lissarca miliaris.

The team suggested that the bivalves reproduce as males while they are still in the "small" stages of development, switching to female organs once they are large enough to brood a significant number of eggs, the BBC Nature reported.

Brooding is a relatively common reproductive trait in Antarctic invertebrates and has been linked to the extreme conditions.

"Brooding is common for small bivalves and has been discussed for many years in Antarctic biology," lead author, Adam Reed said.

"Large yolky eggs that are brooded have much lower mortality than small planktonic larvae, but fewer are produced," Reed was quoted as saying by the BBC.

He explained that in extremely cold environments, development is slowed down so feeding larvae becomes a more exhaustive task.

Brooding reduces the need for long periods of feeding according to Reed, making it a more efficient strategy for many Antarctic invertebrates including bivalves and echinoids.

"We also found that after males become female, the male reproductive tissue persists for a long time," he said.

The stusy was published in the journal Polar Biology.