Have you heard what I’ve been hearing in my garden the past few days? Bzzzzzzz.
Drat! The mosquitoes are back.
Scientists haven’t learned how to keep them from biting us. But they are picking up new clues to the behavior of the insect that is so very annoying for us in Minnesota and so dangerous for people in many other parts of the world.
The whine that I find maddening apparently is sweet, sexy music to a mosquito. The insects make it by flapping their tiny wings, and they harmonize their high-pitched tones to find the ideal mate, according to research reported in the journal Current Biology.
The research by Gabriella Gibson, an entomologist at the University of Greenwich, UK, and colleagues answers a question that’s always puzzled me: Why do mosquitoes give us a warning rather than just sneaking up on us?
It seems that the signal they’re giving to attract potentially perfect mates is more important for survival of their species than the risk of being flattened by a human swat.
The research involved a complex of mosquitoes in West Africa’s Burkina Faso. The Anopheles gambiae complex includes six identical-looking species.
So, how does one mosquito find a mate from its own species if they all look alike?
Here’s how the research team answered that question, according to Science Magazine’s ScienceNow:
Gibson and colleagues collected larvae of the two species — M and S — in Burkina Faso and raised them in the lab. Then they stuck a short piece of wire to their backs with beeswax and brought them within a few centimeters of another bound mosquito of the opposite sex. The pair flapped in place while a microphone recorded their “music.”
The mosquitoes harmonized — but only with mosquitoes of the same form. A pair of two M or two S mosquitoes aligned their wing beats so that the female beat her wings twice for every three beats of the male’s wings. Like a bowed violin string, the beating wings also created higher frequencies, which match when males and females are harmonizing.
The mosquitoes aren’t listening to the high harmonics; they can’t hear in that range. Instead, the scientists said that the insects use a donut-shaped organ near the bottom of the antenna, the Johnston’s organ, to sense when clashing tones are making the antenna vibrate oddly.
Tell-tale mosquito spit
In a separate study reported in the Proceedings of the National Academy of Sciences, researchers in Australia have devised a way to detect viruses in the slobber mosquitoes leave behind when they feed on a sugary source like honey. The research team was led by Andrew van den Hurk of the Queensland Health Forensic and Scientific Services in Coopers Plains, Australia.
The tell-tale mosquito spit could speed up the process of monitoring for dengue fever, West Nile virus and other diseases mosquitoes carry and spread, giving public health officials a shot at detecting the viruses before they actually sicken people.
Some things to ponder while you swat this summer.
