American Scientist

This roundup summarizes some notable recent items about scientific research, selected from news reports compiled in Sigma Xi’s free electronic newsletters

An Unlikely Pollinator

Normally, crickets would just as soon chew on plants as pollinate them. But on a small island in the Indian Ocean, researchers have found a plain-looking orchid (Angraecum cadetii) that depends entirely on a wingless cricket to help it mate. Most of the orchid’s mainland relatives are pollinated by hawk moths, but no such moths live on the island. During 48 days and 14 nights of observation, researchers saw birds, cockroaches, and even a gecko visit the flowers—but only raspy crickets (Glomeremus sp.) removed the pollen. Whether the phenomenon is a quirk of island ecology or whether it’s just been overlooked on the mainland remains to be seen.

Micheneau, C., et al. Orthoptera, a new order of pollinator. Annals of Botany (published online January 11)

No Secret Ingredient

Stradivarius violins, legendary for their rich and expressive tones, remain the standard by which newer instruments are judged. Their uniformly dense wood, or the chemical treatments it received, might contribute to the violins’ unique acoustics—but their varnish most likely does not. A new chemical analysis of minute samples from five Stradivarius instruments, built between 1692 and 1720, reveals a very common finish. The violins bear a simple base coat of oil, perhaps linseed. Atop that is an oil-resin blend, tinted with ordinary red pigments of the day: iron oxide and cochineal. If Stradivari used a rare key ingredient, his instruments have kept the secret.

Echard, J.-P., et al. The nature of the extraordinary finish of Stradivari’s instruments. Angewandte Chemie International Edition 49:197–201 (January 4)

The Sudden Sea

The Mediterranean basin was practically a desert 5.6 million years ago. Then, abruptly, it became a sea. It filled with water in less than two years, when the Atlantic Ocean gushed through the Strait of Gibraltar with 1,000 times the flow of the Amazon River. The Mediterranean sea level rose some 30 feet per day. Although this deluge was preceded by thousands of years of relatively slow trickling, 90 percent of the filling happened during those last several months. Geologists knew that the Mediterranean had gone from desert to sea, but until now, they weren’t sure how fast. New samples drilled from the seafloor at Gibraltar revealed the size and shape of the old flood channel, informing a more vivid reconstruction of the event.

Garcia-Castellanos, D., et al. Catastrophic flood of the Mediterranean after the Messinian salinity crisis. Nature 462:778–781 (December 10)

Pyro-Chimps

Wielding fire is a quintessentially human pursuit. But chimpanzees are pretty fire-savvy too, a discovery that hints at how our ancestors may have first come to tinker with flames. An anthropologist followed a troop of chimps during two savannah fires in Senegal and found that the apes didn’t flee as other animals did. Rather, the chimps waited until the flames drew near, sometimes within 15 meters, then casually moved on. One male displayed toward the blaze and uttered what might be a unique fire-related bark. The apes’ ability to predict and avoid the bushfire is probably a prerequisite to controlling and building fires—steps that eventually happened in the human lineage.

Pruetz, J. D. and T. C. LaDuke. Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal: Conceptualization of “fire behavior” and the case for a chimpanzee model. American Journal of Physical Anthropology (published online December 21)

Stop That Ringing!

Personalized music therapy could soothe millions of people with chronic tinnitus, or ringing in the ears. Researchers custom-edited musical recordings so that eight volunteers could listen to their favorite songs—minus the notes with the same pitch as their tinnitus. After one year of listening to the modified tunes, participants’ ringing ears were quieter, and over-active regions of their brains were more normal. It appears that, when deprived of real sounds at the problem pitch, the brain learns not to “hear” the tinnitus either. Control participants listened to music that lacked randomly selected placebo frequencies, and did not benefit.

Okamoto, H., et al. Listening to tailor-made notched music reduces tinnitus loudness and tinnitus-related auditory cortex activity. Proceedings of the National Academy of Sciences 107:1207–1210 (January 19)

Diagnosing Devils

A deadly contagious cancer could drive wild Tasmanian devils (Sarcophilus harrissi) to extinction within decades. The cancer cells spread from one individual to another during physical contact. But where did the original contagious tumor come from? To find out, researchers compared gene expression in tumors and in several healthy tissues. The closest match was in the Schwann cells—cells that normally protect the peripheral nervous system. Biologists hope that knowing which genes are active in the tumors will help them develop tests and vaccines to protect the ailing marsupials.

Murchison, E. P., et al. The Tasmanian devil transcriptome reveals Schwann cell origins of a clonally transmissible cancer. Science 327:84–87 (January 1)

Like-Minded (Planetary) Neighbors

The hunt for Earth-like planets is heating up. Astronomers have spotted a watery planet that is 2.7 times larger than Earth and only 42 light-years away. It even orbits its star at a nearly-habitable distance. Nearly, but probably not quite: The newfound planet heats up to 400 degrees Fahrenheit during the day. It also doesn’t have any land. Astronomers found this steamy world by monitoring 2,000 nearby stars for recurring faint eclipses caused by orbiting planets. This and other recently discovered small planets show that the technique is working and may soon reveal even more familiar-looking worlds.

Charbonneau, D., et al. A super-Earth transiting a nearby low-mass star. Nature 462:891–894 (December 17)