Day 8, August 12th, 2009

Our last full day. I worked for Angella with Jared and Karen in the lab dissecting caterpillars under the microscope. Angella has been investigating caterpillars' immune response to parasitism by injecting them with tiny, red glass beads, waiting 24 hours, and freezing them. The beads mimic the eggs that wasps and flies deposit into the body of caterpillars. If the caterpillar can, it encapsulates the egg, rendering it harmless. If it can't, the eggs grow and hatch into tiny larvae that feed on the caterpillar as it feeds on plants, eventually emerging from the caterpillars body, and pupating. Perhaps you have seen caterpillars covered with tiny white blobs. The white blobs are the pupae and unfortunately for the caterpillar, when the adult emerges it finishes consuming the caterpillar. When Angella injects the miniscule beads, on the order of 40 - 100 microns, the caterpillar either encapsulates them, or not. If the caterpillar encapsulates the beads, they cover the bead with a dark layer of cells and they no longer appear red. If they can't, the bead stays red. Our job was to carefully dissect the caterpillars, collect the beads and describe their color. Looking at a caterpillar under the microscope was amazing. Their bodies are incredibly detailed inside and out. I spent 81/2 hours glued to the microscope. Angella explained that caterpillars are usually either toxic or have a strong immune system, meaning they are able to encapsulate. Apparently, the toxins that some caterpillars can produce, inhibit their immune system. It appears as though the ability to concentrate plant toxins or encapsulate parasitic eggs is driven by which way the species is attacked, predation or parasitism. Those that are predated upon, evolve toxicity. Those that are parasitized, evolve the ability to encapsulate. In addition, tropical species more often are able to encapsulate while temperate species tend to be toxic. The reason for this discrepancy has to do with the environment in which they live. Tropical rain forests are dense and birds can not see caterpillars so do not eat them. Instead, wasps and flies use their sense of smell to find caterpillars and parasitize them. Temperate forests are more open and birds can see caterpillars and so predate heavily upon them. EIther way, it is a good thing caterpillar densities are controlled. Without parasites or predators our forests would be devastated, compromising the entire forest community. We ended the night with a last night in Cave Creek celebration to the Rodeo Tavern where we had a drink, watched several pool matches, and went on a desert walk where we saw a rare arachnid, the Vinegaroon. On the way back to Cave Creek, we searched the roadway for snakes and with good fortune came across a Mohave Rattler. A great time was had by all.

Day 7, August 11th

Today, I worked with Nat, Jared, John, Aimee, Judy, and Angella in the Coronado Forest along the Crest Trail. We set up two plots, each ten in diameter and collected caterpillars from their target species which included Ponderosa pine, Douglas fir and , lupine. We collected all stages of development and did a leaf count. The site was about 1 hour south up into the mountains at about 8000 feet elevation. The air was cool and sweet, rich in the aroma of pine. We had the afternoon off. Karen Judy, Kathy, Junko, and I went for a hike up to Silver peak. Along the road we found a shrub covered with insects. A little further along we saw a tree covered with curious fruit. Junko suggested that it was pomegranate and sure enough it was. We all shared one. At the trail head, I caught a few glimpses of a bobcat. The trail took us up to a high grassland with fabulous views of the cliff walls that surround the canyon below. That evening, we had a party as we watched the Perseid meter showers.

Day 6, August 10th

As we were waiting for the van to arrive to take us from the Cave Creek Ranch where we are staying to the Southwest Research Station, we saw this odd looking creature raid the peanut butter left out for the woodpeckers. I am told it is a relative of the raccoon, has a prehensile tail, and is called a coati. This morning, I worked with Junko and Nat searching for caterpillars in Juniper trees. We found around 25 caterpillars belonging to 4 different species. On the way back for lunch, I spontaneously decided to try a small, 1 foot tall juniper and off popped a monarch larva! Apparently, juniper is not its host species so it was most likely on the move, looking for a good place to pupate. We continued collecting for two more hours after lunch with less luck. Clouds rolled in and thunder rumbled in the distance. No rain but cooler temps. This evening we attended a very detailed lecture on self medication by woolly bears by Dr. Mike Springer. His research has shown that woolly bears will feed off a toxic host plant only when infected with a parasitoid.

Day 5, August 9th

Today I was assigned to work in the lab with Nat. The caterpillars are kept in ziplock bags with the foliage they were found on. Our job was to arrange the bags in numerical order, account for each caterpillar in each of the bags, take notes on their stage of development, and to clean out their frass (poop). This took all morning. We had the afternoon off and hiked the Chiricuhuan Wilderness in search of the rare Trogon (a bird). Had the company of a graduate student from Wesleyan University who shared her experiences monitoring sea turtles in the Carribbean. After dinner Dave Wagner gave a lecture on the significance of caterpillars and their survival strategies. Everyone here is so enthusiastic about their studies and very willing to share their knowledge in a friendly way. I am learning so much, having a blast, and am surrounded by a breathtaking landscape.

Day 4, August 8th, 2009

Broke into groups. My group went collecting near the Research Station along a very shallow stream. We spent about 3 hours "beating" brush, catching what fell off with a "beat sheet", collecting any caterpillars that we could find, and placing them with some vegetation in ziplock bags to take back to the lab. That afternoon we spent a couple of hours looking for wooley bears. They like to feed on oak trees during the night. As the sun rises they climb down the tree and burrow into the leaf litter along the base of the tree. We did not find any. It has been very dry. We did however find a cluster of caterpillars in a tree. Yours truly climbed up to get them. The remainder of the day was spent walking along the face of a huge rock face searching the vegetation for signs of caterpillar. After dinner, a couple of the more adventurous walked 4 miles down from the Research Station to the ranch as the night fell.

Day 3, August 7th, 2009

Today we made our to the ranch at Cave Creek, AZ where we will be staying. We drove south for a couple of hours along a dry, flat basin. The land was covered with creosote bushes. I learned that they secrete a toxic substance that kills off all other plants so they can reign supreme. A little later as we progressed along the highway and up on altitude, the topography began to change. Mesa's and tall rock faces began to appear. We stopped here to collect some caterpillars, but found very few due to the lack of rain. Later, as we approached the foothills of the Chiricahuan Mountains, we entered an area of dry grasses, followed by thickets of mesquite and acacia trees. Finally, we arrived in Cave Creek which is comparatively quite lush. There are dozens of humming birds flitting around. The creek is dry and so is the air, but the temperature is much more reasonable. We spent the rest of the day setting up the lab at the Southwest Research Station and collecting caterpillars. (On the way to the lab we saw a rattlesnake by the road. It was a four footer!) At night we star gazed and watched the bats feeding on moths. Dr. Wagner set up a vapor light to attract moths. Hundreds came of all shape and sizes.

Day 2, August 6th

We got up early for an introductory lecture on biodiversity. I learned that caterpillars are not only one of the largest and most diverse groups of animals, but are also the main consumers of plant life. I thought it would have been something bigger like horses, deer, or some other herd creature, anything but the caterpillar. So, there are these wasps that lay eggs in caterpillars. The eggs hatch and eat the caterpillar as it eats the leaves of some tree. When they are ready they pop out of the caterpillar, emerge as adults, and consume the rest of the caterpillar. It turns out that this disgusting habit is a good thing because if the caterpillars had their way, they would eat every leaf out there, like the plagues of biblical proportion. Without plants, biodiversity plummets. So, the lowly caterpillar is more important to biodiversity than one might think!

The rest of the morning was spent at the Sonoran Desert Museum, familiarizing ourselves with the native plants and animals, and the heat. It reached 114 degrees today. After lunch, we went out into the desert and began collecting caterpillars by putting a sheet under a bush and whacking its branches with a stick. Our team found 7 teeny, tiny caterpillars about the size of ice cream cone sprinkles. We were very excited.

The day ended with another lecture about the different types of caterpillars. Tomorrow we are off to a very remote site, higher in elevation and a bit cooler. There, we will begin searching in earnest, adding to years of data being used to answer questions about climate change, biodiversity, and the caterpillar.