At work, we have a small wall where passengers can sit and wait. In this wall there are at least five different ant colonies. Today seemed to be the day that the flying ants left the nest, which isn’t surprising seeing as it was both a warm and dry day (which has been rare over the last month).
Due to the nature of my job I got to spend a lot of time around the wall, and noticed, without exception, that all the flying ants were taking off in the same direction, which I calculated to be roughly an easterly direction. Now, today was a very still day, with very little wind, so I discounted the idea that the ants were being blown in that direction. In fact, when an obstacle (such as my co worker) was placed in their flight path, the ants dodged him and then readjusted their course to make it an easterly one. I also discounted the fact that they were somehow being influenced by the sun. I observed this behaviour over a few hours, and the course that they took never changed.
Why do they all head in the same direction, and how do they calculate this direction?
There was also some controversy over what flying ants are actually for. What do they do? Do they move out to form even more colonies for next year (in which case the fact that they all fly in the same direction is even more perplexing, surely it would be better to fan out?) or do they perform some other function?