We’ve had a fruit fly problem at our house for many months. Various extermination methods have failed to significantly reduce their population. When they first arrived, they were quite uncouth and annoying house guests, but over time, I must say, they have become, at least in one respect, better mannered. Specifically, they sobered up and no longer swim in our wine.
The first few generations of flies loved merlot. They couldn’t get enough of the stuff. They loved it so much, I’d find a number of them swimming in it every time I lifted my glass to my mouth. I’d either fish them out and pinch them out of existence, or, I’d just close my eyes and drink—either way, same result for the swimmers, they went to fly hell.
After a while, my daughters tired of the flies swimming in their glasses of juice and declared war on the rascals. They learned to make fruit fly traps consisting of small glassfuls of the flies beverage of choice (sure, they could have used cheap vinegar, but noooo, they insisted on using the expensive stuff…in the name of science). They covered the glasses with saran wrap then punctured the wrap with pinholes (flies check in, but they don’t check out).
They set these traps in the kitchen at night, night after night, and always awoke to glassfuls of drowned flies. Over time, the girls noticed less and less flies in their traps and I noticed I was eating less of them in my merlot (I was starting to acquire a taste for their earthy bouquet). Finally, last week we all noticed and commented that the drownings stopped completely.
Successful extermination? No! Our kitchen fruit fly population is about the same as it was months earlier. So, why do they no longer kamikaze dive into red wine? AA? Cirrhosis? They realized fruit goes better with white?
Apparently, fruit flies possess some degree of mini-cognitive ability. But, I don’t believe that accounts for our fly population going on the wagon. They would have had to pass that information from generation to generation, and I can’t see that happening (hey, Buzz, see that idiot McFly drowning over there? Don’t do that! And tell your kids not to do it either).
My guess is that it was accelerated evolution in action. I think my daughters selected something in or out of the genome of our population of fruit flies with their wine traps. Do you agree? If so, what was the affected trait?
And lastly, if fruit flies can evolve the ability to count, ours had better learn to do something useful soon, like preparing my taxes, or the war will continue.