Mosquitoes have own wing tone

PRETTY IN PINK - Researchers have discovered a unique species of pink land iguanas living on the Galapagos Islands, scientists said. The pink iguana is a different species than other land iguanas, and may be one of the earliest examples of species diversification on the islands. Study was reported in last week's Proceedings of the National Academy of Sciences. (Galapagos National Park via Associated Press)

The high-pitched hum of beating mosquito wings is really a love song, one that males and females modulate in a courtship duet that reaches higher frequencies than scientists had suspected.

Lauren J. Cator and her colleagues at Cornell University found the surprising harmonic convergence by tethering mosquitoes to pins suspended in midair to record the flapping of their wings as they passed a stationery pinned partner.

They also discovered that the wingspeed of disease-carrying mosquitoes differed from others - which may prove useful in reducing their number.

Mosquitoes that don't feed on blood acoustically match the speed of their wing beating while sending mating signals, staying within a range of 300 to 600 hertz. But Aedes aegypti mosquitoes, which are vectors for malaria, yellow fever, and dengue fever, hit high notes at around 1,200 hertz, or an octave and a half above concert A (that's the A closest to middle C).

Scientists had thought that was too high for mosquitoes to hear. But another test using electrodes implanted in mosquitoes' hearing organs found both males and females were sensitive to sounds up to 2,000 hertz.

The discovery opens the door to eradicating dangerous mosquitoes by interfering with mating wingtones.

BOTTOM LINE: Certain mosquitoes match the buzzing of their wings in mating duets whose harmonic convergences are high above frequencies previously thought detectable.

CAUTIONS: Experiments were conducted with lab-reared mosquitoes.

WHAT'S NEXT: Test interfering with mating by sending in males who can't hit the right flight tones.

WHERE TO FIND IT: Science, Jan. 8

To a parent, watching an infant have a febrile - or fever induced - seizure is frightening. A simple febrile seizure is caused by the inability of the baby's immature brain to handle temperature changes, resulting in shaking or unconsciousness. The event, while upsetting, is usually harmless and lasts minutes.

But not all seizures are caused by a sudden fever. Some may suggest a serious disease, such as bacterial meningitis, an infection affecting the brain lining.

Because meningitis can mimic a simple febrile seizure, the American Academy of Pediatrics issued a statement in 1996 suggesting that young infants with a suspected febrile seizure get a spinal tap, a painful procedure testing for meningitis.

Now, investigators from Children's Hospital Boston have compiled statistics suggesting a spinal tap is not always needed.

The researchers reviewed 704 cases of infants with febrile seizure who came into Children's Hospital during the past decade. About 40 percent of the babies received a spinal tap - yet none of the testing revealed meningitis.

The study's first author, Dr. Amir Kimia, warns that babies should be evaluated on a case-by-case basis. "Babies who are excessively sleepy, who have a stiff and painful neck, a bulging fontanel, a rash, or a more complicated type of seizure, are warning signs for meningitis," he says - meaning the spinal tap is still in order for those babies.

BOTTOM LINE: Young infants with simple febrile seizure have a very low chance of having bacterial meningitis.

CAUTIONS: Very ill-appearing babies should still be evaluated for other causes.

WHAT'S NEXT: Investigation of complex febrile seizures, another type affecting infants, to weigh the role of spinal taps.

WHERE TO FIND IT: Pediatrics, January issue, 2009.

SUSHRUT JANGI

Correction: Because of a reporting error, an item in yesterday's Health/Science section about the use of spinal taps in babies incorrectly characterized the warning signs of meningitis. They include excessive sleepiness, a stiff or painful neck, a bulging fontanel (the soft spot on the skull), a rash, and, sometimes, a seizure.