First Full Day of Caterpillar Collecting, Aug. 6, 2011

I awoke early and headed out with a team of five Earthwatch volunteers to collect caterpillars off ocotillo and brush on Portal Road. As we drove away from the lush ecosystem of Cave Creek into more of a desert landscape I knew immediately of the need to get there in the cooler morning time. Excited to see just what type of caterpillars would hang out in this climate, I put my beat stick and beat sheet to work.

 The best way to find caterpillars is to hold a beat sheet, a square of canvas with a wood frame, below a branch and whack the branch with a strong stick. The I search the quadrants of the sheet, full of fallen plant matter, for any larvae. Some the caterpillars I look for are 3 millimeters long, so it is a real practice in patience.

 You can see how small they can be. This larva is in the arctiideae family; it's tiger moth caterpillar. Those black tipped projections that make it look like a miniature vacuum roller are called tufts; this one also has long needle- like hairs on its head and end that can stick a predator. I picked one out of my knuckle, and I'm glad it didn't hurt. I later learned that these hairs are venomous and it is a risky to handle them. Ah, sweet timing!

  To have better luck with a beat sheet, it helps to look for leaf damage. Even some bird predators look for signs that a caterpillar is feeding on a plant's leaves to know where to find lunch.