Random Samples

Science  23 Jan 2009:
Vol. 323, Issue 5913, pp. 443

You are currently viewing the .

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution


    Native Vanilla hanging from the Wile Orange in the Seychelles. CREDIT: RBG KEW

    Time has taken its toll on the 832 paintings in the Marianne North Gallery, a show of botanical art and landscapes at the Royal Botanic Gardens, Kew, outside London that has been on continuous display since 1882. A restoration project is under way with the help of a £1.87 million grant from the Heritage Lottery Fund, but another £1 million is needed. So the gallery is inviting members of the public to “adopt” a painting for £500, £750, or £1000. So far, 187 of the works have been taken. The collection, including many vanished landscapes, has a unique value as a “testament of what we've done to the world,” says Kew conservator Jonathan Farley.


    Was the story of Noah's Ark inspired by a real event? In 1997, two marine geologists proposed that about 7500 years ago a torrent of water from the Mediterranean swelled the Black Sea, scattering early farmers into Europe and giving rise to the biblical flood myth. But the tide has been turning against the idea (Science, 17 August 2007, p. 886). Now a study taking a new approach to the question has concluded that the flood was little more than a trickle.

    A team led by Liviu Giosan, a marine geologist at the Woods Hole Oceanographic Institution in Massachusetts, bored a 42-meter core into sediments in the delta of the Danube River in Romania, where it empties into the Black Sea. The delta's geography has remained stable over the millennia, so the team considers it a better indicator of ancient sea levels than the Black Sea sediments used in earlier analyses. The team members also radiocarbon-dated mollusks from the sediments. In the January issue of Quaternary Science Reviews, they report that when rising Mediterranean waters started flowing into it, the Black Sea was at least 50 meters higher than the original estimate—greatly reducing the potential for flooding.

    “It's a fascinating piece of work,” says Chris Turney, a geologist at the University of Exeter in the U.K. Giosan and William Ryan of the Lamont-Doherty Earth Observatory in Palisades, New York, a co-author of the 1997 study, plan to resolve the debate once and for all by applying state-of-the-art dating techniques to both Danube and Black Sea sediments.


    For the first time, scientists have discovered a vertebrate that uses mirrors to see.

    The brownsnout spookfish, a 10-centimeter denizen of tropical deep-sea waters, has taken an unbeaten path during its eye evolution, researchers report this month in Current Biology. To keep watch on things both above and below, the fish has developed eyes with two parts. One captures the dim remnants of sunlight from the surface, using a conventional lens to focus light. The other faces downward, picking up the even dimmer flashes of bioluminescence from both predators and prey, such as small copepods. For this, instead of a lens it uses mirrors—tiny reflective crystals that harness wayward flashes and beam a high-contrast image onto the retina. The mirrors snare more light than the lens, which absorbs some photons as it refracts.


    “It's a neat trick,” says Sönke Johnsen, a visual ecologist at Duke University in Durham, North Carolina. “Nobody's ever seen anything like this in vertebrates.” Study author Ronald Douglas, a vision scientist at City University London, agrees: “It seems such a good idea that I'm surprised that other animals haven't evolved it.”


    Once nearly eradicated, bedbugs are making a rapid comeback in cities in the United States and Europe. The nasty bloodsuckers have been kept in check for decades largely thanks to insecticides called pyrethroids. Now, they're growing increasingly resistant to the compounds.


    To find out why, researchers led by John Clark, a toxicologist at the University of Massachusetts, Amherst, ran genetic comparisons between pyrethroid-resistant and nonresistant bedbugs. In the current issue of the Journal of Medical Entomology, Clark's team reports that the resistant bugs carried two mutations in the gene that encodes the sodium channels in their nerve cells. Pyrethroids force those channels to stay open, paralyzing and killing the bugs. The mutations prevent the insecticides from binding. Scientists have found 26 other related mutations in cockroaches and other resistant insects, Clark says.

    “It's bad news” for pyrethroids, says Coby Schal, an entomologist at North Carolina State University in Raleigh, who thinks sodium-channel resistance is likely to spread rapidly to other bedbug colonies. With few insecticides safe for home use, Schal says, researchers are racing to find new compounds.