Fruit Fly Enemy

I learnt about fruit flies when I was in the last year of high school and was introduced to genetics. After Mendel and Morgan, my genetics manual said that fruit flies (aka, the gnats I chased off of my endlessly flavourful apples or damagingly sweet grapes and plums) had such a variety of characteristics (genetic traits), they made an ideal medium for genetics. Better than Mendel’s peas! After that I treated fruit flies with less animosity and, dare I confess, I started to like them. Did they have red eyes? Short wings maybe? A few more genetics courses later, during graduate school, and I started to respect them. So much of the progress in genetics was due to them and so many of their genetic traits were similar to those of mice and even humans, who wouldn’t tip their hat to THE gnat? This relationship was momentary, and soon gnats fell off my interest, but one interesting trip to South Australia twenty years later and gnats returned to intrigue me. Indirectly. Three quarters of Australia's irrigated crops and pastures are grown in the Murray-Darling Basin, as the mighty Murray River is the third largest navigable river in the world after the Amazon and the Nile. This fruit and vege basket of Australia is apparently fruit fly free and, in this entire area, fruit flies are a feared pest. So much so that approaching the Basin, warning signs bloom on all roads, telling drivers to discard in special containers any fruit or veges they may be carrying with them. The problem is that there is no information offered as to why this food has to be discarded. No explanation is given about the Basin being free of fruit flies and that these creatures, which I assumed are omnipresent in the world, would need to be kept off the area. No sign explains that fruit flies destroy the crop by using it to reproduce. The choice of fruit and veges in Oz is very limited and the prices are ridiculously high, so past this threatening sign ‘throw it out or pay a fat fine’ kind of thing, I was thinking “should I trash THE big, red, healthy looking, juicy apple in my backpack or should I sneak it in and eat it as planned after dinner? IF I don’t get caught and lose the apple anyway, just in a more expensive way…” I decided to take the risk. I ate the apple in the hotel room after dark, with the curtains down, fearing an imaginary fruit and vege police. Still, I could not grasp why the insignificant gnat is an enemy of such proportions! Locusts, yes, but gnats? The following morning we hopped back in the car and drove from Mildura towards Mungo National Park. It was a week day and a few kilometres outside the town there was a fruit and vege check point. We stopped behind another 10-20 cars and waited (forever!) to be checked (car and trunk) for the “forbidden fruit”. You can see in the picture the signs posted at the check point, but we had the confidence of being “clean”. A seriously unfriendly lady refused to tell us why fruit flies are such a threat (she didn’t look like she knew, anyway), asked us to open the boot (trunk), she looked around and then found a cooler. We let her open it and there it was, another apple, the one left over from yesterday’s lunch! She suspiciously asked if there were more, took it and threw it in the rubbish (trash). No fine (what a relief!), but off we went after being 20 min behind schedule and with about 500 km left to drive for the day. We sped from the checkpoint happy not to had been fined, but, short-lived victory, a police car started to flash its lights right behind us very soon... Ooops, we realized we literally sped off from the checkpoint, maybe too happy to remember speeding is also fined. At least we knew why we paid the fine!