I found two awesome things yesterday, and both of them became more intriguing upon a second look. The caterpillar above is, I believe, a fourth instar western tiger swallowtail. Take a gander at these pictures from the Liang brothers’ blog for comparison. After its last molt (the fifth “instar”), the eye spots on the top become mainly yellow and the whole caterpillar is beefier and more smoothly green. I’ll try to go back to the spot I saw it in a few days. Maybe I can catch it before it makes a cocoon. But here’s the fun part: As I was taking pictures, moving my phone and lens closer to it, I noticed something yellow coiling out of it:
Swallowtail caterpillars have this amazing defensive maneuver where they extend yellow-orange glands above their head. People say it makes them look like snakes, which would scare away any birds interested in snacking on a juicy caterpillar. The marks on their backs look like eyes and the forked “osmeterium” looks like a snake tongue. So cool!
The second interesting thing I saw yesterday was a group of ants gathered around these red galls on an oak branch. Ants are known to “tend” some galls, including these “clasping twig” galls. They sip the honeydew the galls produce from the sap of the tree. The ants were at a weird angle to me, and I took two pictures from above the branch, not even knowing if they were in focus. When I got home I found out I’d actually taken video and it was really interesting.
As you can see, this is a frame from the middle of a two-second video. The ant has its jaws open and there’s a tiny (I think) wasp in its grasp. It might be the wasp that made the gall, but I have no clue if it’s even the right time of year for them to emerge. I don’t have enough footage to show whether the ant was eating the wasp, moving it out of the way, or gathering honeydew from it. I’m also curious why the ant’s abdomen is bent down underneath it.
I enjoy the fact that finding interesting insects often produces more questions than answers.
Cheers!
Ticklehead 