A Beetle, a Bur, and the Potato: An Introduction to Ecology

To introduce an ecology course to beginning students, I needed a familiar plant-animal combination that could illustrate a variety of ecologic principles. There are dozens of such combinations that biology teachers can search out and use for this purpose or to provide illustrated talks to public groups. The organisms chosen can be illustrated with slides or collected specimens, or they may be observed on a field trip. My own childhood in the rural Midwest had provided numerous intimate associations with a variety of organisms. Among them were the buffalo-bur nightshade, Solanurn rostratum Dunal, and the Colorado potato beetle, Leptinotarsa decemlineata (Say). Early experiences in bare feet had taught me to avoid the spines projecting from the buffalo-bur. Our reliance on the Irish potato as a major food source, especially during the depression of the 1930s, encouraged the control of beetles in the potato patch. Both hand-picking and spraying with lead arsenate or Paris green were used when beetle populations threatened our food supply. The interrelation of the potato beetle, the buffalo-bur, and the potato became the vehicle of my introduction to ecology. The Bur