A Deadly Enemy Older than Man: The Buzz of Death

Mosquitoes transmit disease to over 700 million humans a year, with a resulting death toll in the millions (wikipedia). To this point, the insect repellant DEET is the most effective defensive weapon against these disease vectors, other than thick clothing and strong netting. But humans are slowly beginning to decode the language of mosquito smell rceptors.

Scientists at UC Riverside are discovering an array of common chemicals that can inhibit, blind, or lead astray the CO2 receptors of mosquitoes.

Vanderbilt University researchers have gone further, and developed an entirely new class of insect repellant which is thousands of times more effective than DEET.

NewScientist
But now that genetic engineers have become interested in the mosquito problem, we are beginning to see new strategies which are more clever than ever. The illustration above reveals two contrasting approaches to species eradication -- the sterile male technique vs the autocidal technique.

...if autocidal technology lives up to its promise, it could be about as environmentally friendly as pest control can get. It could largely or entirely replace pesticides, and it affects only the target species. Last but not least, it is hard to see what could go wrong. _NewScientist

The autocidal technique produces females which either die before maturation, or which are physically disabled and unable to mate.

Generally, genes that cause a reproductive disadvantage will tend to disappear from the population over time. But there are a number of factors which could alter that Darwinian equation.

If the autocidal mosquitoes were also given traits that conferred a reproductive advantage for themselves -- super powerful sexual attractant pheromones for example -- as part of an overall genetic package, the autocidal trait would spread more quickly.

Likewise, if automated stations were set up in the wild to periodically release new batches of autocidal males, the process could be reinforced over an extended period of time.

If the autocidal trait caused sterility in females, rather than death or disability, the process of species extermination would be accelerated.

And so on. It is easy to imagine dozens of ways to augment, accelerate, or perpetuate such a process of ongoing extermination.

Alert readers will have recognised the return to the New Scientist article on species extinction, applied here specifically to mosquitoes.

But as noted in the NS article, similar techniques could be applied to virtually any species that reproduces sexually. Also as noted in the NS article, the genetic engineers have just begun to think of different approaches to the mosquito problem. This ball has just begun to roll down the hill.