I had noticed over the past couple of months that often a line of flower petals and leaf fragments would extend from one side of the yard across the driveway. Only a little line of them, though. It seemed like a very mysterious pattern for wind to arrange them in.

By now, you’ve probably beat me to the conclusion that should have been obvious to someone studying biology: ants!

They are only active around dusk, busying themselves as the pavement cools, then tucking themselves away later, often leaving a trail of detritus in their wake along the otherwise invisible superhighway, but only about 3 meters or more from their nest. I have this image in my head of the word going out along the line, “Time to go home! You have three minutes to get there!” and those ants that are far away dropping their colorful burdens and booking it. Or maybe it gets too hot or too cold to continue foraging, and those closest to the nest continue dragging themselves forward, goal in sight, but those further away give up on their final contribution for the evening to concentrate solely on dragging themselves in, shivering (not really) or heat exhausted (probably not at night, but anyway…).

My roommates had understood what was going on far before me, and have even provided some commentary.

“Look, they’ve been decorating!” PJ told me the other night. And so they had. The green little mountain had turned yellow from palo verde blooms, and then red from another flowering shrub a few days later.

Last night, I went on a jog up Tumamoc Hill at sunset to get a look at where the buffelgrass invasions were. (Tangent: I’m pretty convinced that sunsets get more beautiful as it gets hotter. I have no idea whether there are any heat- or humidity-related processes that actually change the visual effect, or whether the relief from burning radiation is just greater, later in the evening, during the warm months.) Ss I stepped through the gate onto the road that winds its way to the top, I was most certainly not alone. An antlike superhighway of people extended to the top of the hill, there and back, passing one another. We were not encouraged to carry large vegetative structures off the hill with us as ants would, but I did notice some palo verde had set seed up there, and was temped to try germinating them back at the lab…