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?