If I leave a cut apple on the counter in my closed kitchen, an hour later, fruit flies are sitting on it. Where do they come from?
I’ve wondered this same question for a long time. Even in the middle of winter, when my house is surrounded by a foot of snow in sub-freezing temperatures, I will get sudden out-bursts of fruit-flies in random spots inside my house; as if seemingly out of thin air.
Before Pasteur, many people thought it was spontaneous generation.
put that apple slice in a paper bag and then close them in and trash them out.
If you want to see where they are comming from, watch the Honey Wagon as it works its way up your street/alley.
a dish of sugar water w/ dawn dish soap on the counter over night will give You something to count 
Curious to know how many of us did not have to google “Honey Wagon” to understand that post.
I did google “honey wagon” and I still don’t understand that post.
In that case I’ll do nothing and wait…
Same here. 
I don’t believe I have a “honey wagon” in my neighborhood (I always thought that was the term for a Port-a-Potty truck or trailer), but I’ve had fruit flies seemingly generate spontaneously in my kitchen in the wintertime. They were apparently coming from the drain/garbage disposal, and once I poured a good amount of hot water down the kitchen sink, they went away, at least for a while.
In the case of fruit flies, they were right all along.
Sorry all, but that is what we call a Garbage Truck in this area.
dumping can over the sideboard of a standard dump truck back in the mid 60’s was one of my first jobs and i made $0.10 a day. there were NO bags then and the cans were at least 3 times heavyer than a can of today and we pounder the crud out of them, litteraly.
Where?..a bit back i discovered a banana in an enclosed plastic bag. Yes there were tiny flies in there which leads me to deduce the flies come from the fruit its self…
Article on subject:
Some attach themselves to fruit, some live in the sink pipes, some live on a wet mop.
In my house they seem to be generated by the soil that the houseplants grow in. Made worse by me bringing in garden plants overwinter.
I don’t understand the post, and I won’t respond to it.[/LB]
Empty bottles or cans of beer and wine make excellent breeding spots for fruit flies.
Decimal skip?
In all fairness he was really bad at his job.
<raises hand> 
Oh, stewardess! I study fruit flies!
Just some facts for you to chew on. Fruit flies lay their eggs in soft, mushy rotting fruit, by preference. After a few days, the eggs hatch and release larvae - maggots, if you prefer. Initially, they’re so small that they’re barely visible to the naked eye. They go through two moltings, getting up to the size of a largish grain of rice before they finally pupate. All told, it’s about nine days from egg laying to the emergence of a new adult under optimal conditions.
They are strongly attracted to a variety of chemical smells, including ethanol, which is produced by the rotting process. And they love yeast.
Also, the male fruit fly produces mind-controlling zombie proteins in his sperm that reprogram any female he mates with. That’s not really relevant; I just like to tell everyone I can about it.