March 30, 2009 -- To switch from male to female and back again without the help of surgery is a feat that only a handful of organisms can accomplish, including some types of fish, shrimp, snails and worms. Now, a new study adds mushroom corals to the list. It is the first study to show that any coral can change sex in either direction, let alone both. Understanding why and when some corals make the switch may eventually help scientists protect them from the stresses of a changing environment. For now, the study remains a fascinating window into the biology and evolution of these corals. "We know in detail the reproductive patterns of more than 500 coral species, but no one reported before on the fact that some coral species may change sex," said lead author Yossi Loya, a zoologist at Tel Aviv University. "I believe this was quite a big surprise to all coral reef scientists." Mushroom corals belong to a family called Fungiidae. They are solitary, mobile species that live throughout the Pacific and Indian Oceans. Mushroom corals are abundant and diverse, but how they reproduce is something scientists haven't known much about. Related Content:
To learn more, Loya and a colleague traveled to a patch reef near Okinawa, Japan. The reef is home to tens of thousands of mushroom corals, representing a dozen species. In 2004, the researchers collected, weighed, measured, and tagged about 15 individuals from two species. Each coral then got its own aquarium in the lab. That July, about five days after the full moon, the mushroom corals did what many corals do -- simultaneously release sperm and eggs. In the ocean, these gamete explosions produce larvae that drift off to become new corals. In the lab, the scientists collected the gametes and looked at them under a microscope. Then, they returned the corals to the sea. Initial analyses showed that each coral produced either sperm or eggs. Some types of corals are hermaphroditic, with both male and female parts. But mushroom corals appeared to be just one or the other. The researchers repeated the same experiment in 2006 and 2007 -- with both the same individuals and new ones. The results grew increasingly surprising. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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