Earthwatch Day 6

Every morning we sit by the wildlife feeding station at Cave Creek Ranch until our ride comes to take us to the research center. Today we were treated by a visit by a coatamundi at the bird feeder site! He/she kept on eating while we all took pictures, not in the least bit worried about us. The hummingbirds were plentiful as always. Their wings flap so fast, you can't see them in the picture!

After breakfast, groups got their assignments for the day – my group (Kathy, Amy & I) were assigned to collect and record data using the “plot” method. This method is used to collect quantitative data from several elevations to compare caterpillar populations.

Using 2 ten-meter lengths of rope tied together at center, we created 4 quadrants of a circle by extending each leg of the rope. We placed the center knot at the “focus” tree. Then we used a PDA/GPS to determine elevation, lat/long, and to mark the exact location on a map. Next we “beat” all the species of herbaceous plants that we would focus on within the plot. Any caterpillars found were collected and bagged.

One of the hardest things to do was to estimate a count of the leaves on every plant within the quadrant. This gives Dr. Dyer a way to estimate populations and have a standard to work from. He explained to us that he has collected data from different locations with different elevations in five places for the last 15 years or so. This same method is used at each research site. The whole process makes you realize how labor intensive it is to gather accurate data!

My team completed 4 plots by the end of the day. In the afternoon we had some time to check out the nature shop. I think it’s very cool that this research center is run by the American Museum of Natural History! The office staff explained that researchers from universities all over the country reserve time in their labs to do research. When we left, there was a resident kitty that was hanging around out front. I wonder what research project (s)he’s working on?

After dinner, we listened to an interesting talk by a fellow caterpillar researcher from Wesleyan University, Michael Singer. Using slides, Mike described two research projects he has been working on. In one, he questions whether it is beneficial for caterpillars to be specialists rather than generalists in terms of food/plant host. Specialists seem to be better adapted to avoid predators (such as birds). Often this is by visual crypsis (looking just like host plant) or chemical toxicity acquired from their host plant. In the second, he investigates “self-medication” in caterpillars. Caterpillars can sequester chemicals from some host plants that actually prevent or help stop parasitoids! They may change their diet because of this, but is it learned or instinctual behavior? You might think…who cares? But could there be a connection to why humans sometimes like the flavor of spices, bitter herbs, garlic, etc? Could there be medicinal properties in some plants? It’s all very interesting to ponder.