Mosquitoes serenade each other before sex

January 9th, 2009 - 1:21 pm ICT by IANS  

Washington, Jan 9 (IANS) Mosquitoes flap their wings and modify their tune to create a harmonic duet just before mating, scientists have discovered.Entomologists have discovered that male and female mosquitoes (Aedes aegypti), which can spreads yellow and dengue fevers, “interact acoustically with each other when the two are within earshot - a few centimetres of each other”, said Ron Hoy, professor of neurobiology and behaviour at Cornell University.

“The frequency at which males and females converge is a harmonic or multiple of their wing-beat frequencies, which is approximately 400 hertz [vibrations per second] for the female and 600 hertz for the male,” said Hoy. The study, available online, will be published in a February issue of Science.

Mosquitoes adjust the harmonic resonance of their thoracic box to produce a harmonic frequency that converges at a frequency that is the female’s third harmonic (three times her fundamental frequency) and the male’s second harmonic (two times his fundamental frequency).

The study also is the first to definitively show that contrary to previous thought, female mosquitoes are not deaf, according to a Cornell write-up by Susan Lang.

To study mosquito mating calls, the researchers tethered mosquitoes and flew them past each other while recording the flight tones with a special microphone.

Co-author Benjamin Arthur, postdoctoral researcher in Hoy’s lab, placed electrodes in the mosquitoes’ auditory organ in their antennae during playback to measure physiological responses of the mosquitoes to the sounds of potential mates.

The researchers hope that their work will provide new ways to better control mosquito populations in places where yellow and dengue fevers are significant problems.

Dengue fever affects 50 million people annually, and two-thirds of the world’s population is at risk. Lately, it has reached epidemic levels in Asia, South and Central America and Mexico, where its incidence has increased by more than 300 percent from year to year.

“By studying these flight tone signals, we may be able to determine what kind of information males and females consider important when choosing a mate,” said co-author Lauren Cator, a Cornell graduate student who works with Harrington.

“This will allow us to release ’sexy’ transgenic or sterilized males that will be able to successfully compete with wild populations.” No dengue vaccine is available, and no treatment exists beyond supportive care.

Tags: , , , , , , , , ,

Posted in World |