Thursday, April 29, 2004

For obvious reasons, I can't post any confidential details of my postdoc search here, although I'll be glad to update friends via private e-mail. I can, however, celebrate the good news that my visiting associateship at Michigan State has been extended; I can remain an official employee for up to two more months, with the understanding that I can leave earlier if I line up something longer-term that has to start sooner. So, instead of spending the day saying goodbye to people, I spent a half hour getting my parking sticker updated. After that, I took my lunch -- low fat tuna salad on multigrain bread, carrot sticks, fruit, and the obligatory Talking Rain -- out into a courtyard behind the Natural Science Building, where the flowering shrubs were buzzing with Xylocopa. Unfortunately, half of the courtyard was also buzzing with lawn tractors and weed whackers, so I took the extra time to find a secluded spot, with a whole bench to myself, next to a brick-paved path. And, where there are bricks, there are pavement ants. I then remembered that tuna baits are an important part of a myrmecologist's toolbox, so when these (putative) Tetramorium proved to be a bit shy, I pulled a couple of small tuna fragments out of my sandwich and slapped them down on the bricks. One was a thin chunk of meat about a centimeter long; the other a fragment about a fifth that size.

Now, I have to admit that the reaction of these ants was not quite what I expected. My free-range Crematogaster can not only smell food before it arrives, but as far as I can tell they can teleport themselves to it. The pavement ants, however, just sort of drifted toward the tuna fragments. I think it took two or three minutes for the first ant to find the food, although I'd placed it only a few centimeters from a small group of workers. Then, one of them tugged at it ineffectually, ran around it a few times, tugged again, and eventually ran off. After about five minutes, there were some minor signs that a trail was being followed, and all of three ants were actually poking at the tuna -- when another ant, this time a carpenter ant (Camponotus), stumbled across the same bait and zoomed in on the large piece.

For a carpenter ant, this one was rather small, but even a small carpenter ant dwarfs a pavement ant. The previously easygoing pavement ants, though, did not take the presence of this big lug in stride. Whenever the carpenter ant came face-to-face with a pavement ant, the smaller ant lunged at her. The carpenter ant darted around nervously for a while. The smaller ant lunged again. Finally, some small light bulb must have turned itself on within the tiny blob of glop that is a carpenter ant's brain. The big ant wheeled around, darted away from the smaller ants, grabbed the smaller of the two pieces of tuna, and ran like hell.

When I got up from the bench a few minutes later to go back to work, the carpenter ant was still tottering away at top speed through the grass with her huge prize. The pavement ants seemed to have forgotten about her. Hell, most of them seemed to have forgotten about the tuna; there were never more than three of them at a time working on the big chunk. I'll have to come back another day and bring them a different kind of food -- maybe some cookie crumbs, or else the remains of the drivers who twice dented my new car in the Nat Sci parking lot. (Hell, another two months at work, and I can afford four more such dents.)


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