Catching Flies, Part 2

This morning when I got to work I decided to build a fruit fly trap that would hopefully work better than simply setting out a bottle of malt vinegar. Incidentally, the lid full of vinegar worked better than I thought it would. When I dumped it out, I found there were almost a dozen fruit flies that had gotten into it and sunk to the bottom. It turns out that bottle of vinegar also had some liquid dish soap added, which I heard from several places helps in its trapping ability. Apparently the soap breaks the vinegar's surface tension, making it so the fly would actually sink in rather than be able to sit on the top and fly away to safety.

But the downside of something like that is that it still primarily just attracts the flies, and doesn't really trap them. It's only the few that are foolish enough to go right up to the vinegar that meet their demise. Hence the reason for a trap. I grabbed a disposable plastic cup from the closet at the office, then poured a bit of the vinegar/soap mix into it. Next I took a piece of card stock from my recycling box, cut a rough semi-circle from it, then rolled and taped it into a cone shape. After cutting the tip of the cone off, I put it into the cup and put tape around the edge to both hold it on the cup and make sure it was sealed. The important thing is that the only way in or out was through the hole in the cone.

And it worked great! It seems that after the flies are attracted into the trap thanks to the vinegar (I've heard that apple cider vinegar works best though—I'll have to bring some in tomorrow morning) they are simply too stupid to exit through that same hole they entered through. Seriously, throughout the day I watched several of them crawling around the cone inside the cup and go right up to the hole—then turn around and head back the other way. Eventually they either fall into the vinegar or try to land on it. Even if they didn't, they still would be stuck inside the cup rather than flying around annoying me.

At the end of my work day I picked the cup up and looked inside, and counted 35 flies that I could see. Since I could only see what was around the edges of the cup due to the dark malt vinegar, I'm sure there were more in there that I didn't notice so I've been assuming there were around 40. 40 fruit flies trapped, after only 8 hours. In comparison, the filled cap only trapped about a dozen, in 16 hours. Triple the kill count in half the time. Not bad! I wonder what it'll be like when I get back to work in the morning...