# http://www.straightdope.com/mailbag/mfruitfly.html

**URL:** <https://boards.straightdope.com/t/http-www-straightdope-com-mailbag-mfruitfly-html/208310>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [October 19, 2003, 4:31am UTC](https://boards.straightdope.com/t/http-www-straightdope-com-mailbag-mfruitfly-html/208310 "2003-10-19T04:31:20Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![CHKopinski](https://avatars.discourse-cdn.com/v4/letter/c/5daacb/32.png) [@CHKopinski](https://boards.straightdope.com/u/CHKopinski)\
**Post date:** [October 19, 2003, 4:31am UTC](https://boards.straightdope.com/t/http-www-straightdope-com-mailbag-mfruitfly-html/208310/1 "2003-10-19T04:31:20Z")

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The reply to this kind of explains why you see fruit flies, but it still doesn’t anser where fruit flies come from! Where all all the fruit flies and what are they living and feeding on until there is fruit to ferment? I could see this in the tropics where there is almost always some fruit coming ripe at any given time of the year, but here in the temperate zone there is just no fruit to ripen until sometime in the fall. Is this a case of our supermarkets providing a year round breeding habitat for fruit flies? Where would a temperate zone fruit fly estivate until it’s preferred meal is available?

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**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\
**Post date:** [October 19, 2003, 8:07pm UTC](https://boards.straightdope.com/t/http-www-straightdope-com-mailbag-mfruitfly-html/208310/2 "2003-10-19T20:07:52Z")

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Hi and welcome! 🙂

[http://www.discovery.com/area/skinnyon/skinnyon970718/skinny1.html](http://www.discovery.com/area/skinnyon/skinnyon970718/skinny1.html)

> [@](#):
>
> “They’re native to most areas of the country,” says Colorado State University entomologist Whitney Cranshaw. “They come from outdoors.”
> 
> \< snip \>
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> Fruit flies prefer a diet of yeast, that marvelous microbe that eats fruit and spits out alcohol. Since flies disdain unripe fruit, and since that is precisely the sort of colorful paperweight that supermarkets tend to distribute, it’s more likely that your Drosophila melanogaster came from the great outdoors than from the grocery store.
> 
> \< snip \>
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> And once they’re established in your house, they can sustain themselves on an impressive range of nutrients. They can live on the slime inside a sink drain. They can flourish on a sour mop. They’ll eat damp flour or food fermenting quietly in a crack in the floor. They’ve even proven capable of existing on a diet of alcohol fumes, their bodies deploying a special chemical that converts the alcohol to nourishment before it can poison them.