In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them.
The thistle caterpillar is the larval stage of the painted lady butterfly. The adult insect migrates into Iowa each year from Texas and Mexico. Eggs are laid on both thistle and soybeans. The caterpillar is easily identified by the spines that resemble Christmas trees that have lost all their needles.
While adult butterflies will feed from a wide variety of nectar flowers, caterpillars typically have very specialized diets. For instance, plants in the mallow family are favored by the west coast lady and the common checkered-skipper caterpillars, while monarch caterpillars feed solely on milkweed.