This idea exploits behaviour selection and the fact that insects have short generational spans.

Flies are attracted to food sources, on which they often lay eggs, largely by odour. When they arrive at the food source, they then investigate by touch and taste.

The system requires the distribution throughout populated areas of scented lure traps.

These traps have a slowly-moving strip of material, textured to resemble an insect food source. They emit a synthetic odour of decay; alternatively, under the strip is located a suitable portion of decaying material which will attract flies, behind a fine mesh which does not allow the flies access to it.

The flies land on the strip, attracted by the smell. Thus reassured, they lay their eggs on the strip and depart.

The strip then passes under an intense ultraviolet source which sterilises the eggs.

However, there is a cunning twist.

The lure-trap also emits a synthetic smell, uniquely designed to be detectable (though not necessarily attractive) to insects at low concentrations, but very difficult for humans to detect. This odour must not resemble anything in the natural environment.

Flies which lay eggs in the presence of this smell will have a lower chance of successful reproduction. Flies that avoid the "signature" smell will have a better chance.

Over time - a relatively short time - flies will evolve that actively avoid the signature smell despite the presence of an attractive food odour.

All that is neccesary is to keep the lure-traps running in urban areas to maintain the selection pressure.
-- 8th of 7, Aug 14 2010

Beanie, is that you??? Nah, guess not. Bun with a cunning twist [+].
-- Grogster, Aug 14 2010


I thought this was gonna be make them run a maze and kill the successful ones.
-- FlyingToaster, Aug 14 2010


Or, instead of a maze, have the fly fight against a powerful air current in order to reach the food. Kill the strong flies that make it there, and eventually you'll have a population of weak flies that can't dodge a rolled-up newspaper.
-- DrWorm, Aug 14 2010


[+]. Actually the synthetic smell could be human sweat. Then flies would end up avoiding people. Unfortunately, I can't see this idea working. There are a bajillion flies in the world, you would have to plant a lure every few hundred yards across the surface of the earth, for it to have any effect. If you limited the lures to populated areas, unaffected flies would fly in from the 'burbs.
-- AntiQuark, Aug 15 2010


I don't understand why, after what must be thousands of fly-generations, by natural selection they haven't evolved to fly through the *open* part of a window.
-- mitxela, Aug 15 2010


must be something to do with they're not seeing an invisible barrier
-- po, Aug 15 2010


There's something very Zen about that, [po]

// limited the lures to populated areas, unaffected flies would fly in from the 'burbs. //

You'd take the kill zone half a kilometre outside the perimiter.

The thing is NOT to kill the "incomers" - they absolutely must interbreed with the survivors, so as to spread the "avoid the smell" gene throughout the entire population.
-- 8th of 7, Aug 15 2010


// You'd take the kill zone half a kilometre outside the perimiter. //

How far do flies fly in their lifetime? The kill zone would have to be at least that big. Probably bigger, because there would be a steady flow of normal flies arriving, diluting the avoidance gene.
-- AntiQuark, Aug 15 2010


this summer, I have been photographing hoverflies (flowerflies) before which I have never ever taken any notice of them whatsoever - up close they are strikingly beautiful.
-- po, Aug 15 2010


natural selection would produce a solution that defeated the mechanism entirely. This is the "third way" that your idea fails to recognize, unless your mechanism is adaptive the other species will eventually or immediately become resistant to it. Your flytrap needs to be alive for your plan to succeed. The eventual result might be that both flytraps and flies consume nearby humans.
-- WcW, Aug 15 2010



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