People often think of carnivorous plants as being tropical monstrosities, but many species make their homes in cold climates, and some can even be found in the Chicago region. The Museum's Biology Department took a trip several years ago to the Indiana Dunes' Pinhook Bog (open only to guided tours due to the fragility of the ecosystem) where we saw sundews, pitcher plants, and bladderworts--all species that make up for the low-nutrient peat moss they grow in by digesting insects. Combined with the rare orchids, blueberry-lined walkways, and the fact that the ground moves when you walk on it, it was one of my favorite daytrips. Volo Bog, north of Chicago, is home to such strange plants as well.
While the Venus Flytrap (Dionaea muscipula) is the most iconic carnivorous plant outside of Super Mario Brothers and Little Shop of Horrors, our local meat-eating flora have plenty to offer. Pitcher plants (Sarracenia purpurea) have leaves that form a tube that collects rainwater. The attractive red coloration draws curious creatures to the rim of the "pitcher." Occasionally an insect will fall down the slippery slopes into the pool of rainwater and be trapped, and shortly thereafter digested. But since plants lack teeth, the plant has to hire someone else to chew its food. It is said that "If you build it, they will come," and a host of invertebrates make their home in the water of the pitcher plant, forming a mini-ecosystem inside the leaves of one plant. The top predator is usually the larva of the Pitcher Plant Mosquito (Wyeomyia smithii), one of several animals which lives only inside pitcher plant puddles, and nowhere else. Please don't think we should fog the bogs, though; the pitcher plant mosquito doesn't go for people. Eventually bits of the prey are chewed, shredded, digested, and excreted by enough little bugs, bacteria, and other critters that nutrients from the victim's body become usable by the plant.
Drosera rotundifolia, the Downy Sundew, takes a different tactic. Its leaves are covered with red, tentacle-like protrusions, and coated in a sticky, sugary substance. When prey come investigating they get stuck. The tentacles then curl up around the insect, and the plant begins to exude enzymes to extract precious, nitrogen-containing compounds that are otherwise hard to come by in the sundew’s habitat. This is because in bogs, the high acidity of the peat moss and water inhibit the breakdown of organic matter, so nutrients remain locked away instead of cycling through the ecosystem as they might in more garden-variety soils. Many Drosera species have become so adapted to their conditions that they completely lack the enzyme that enables other plants to absorb nitrogen from their roots.
While our collection is small, the Museum does maintain several living examples of carnivorous plants in our Mysteries of the Marsh exhibit. As these are wetland plants, they are members of some of the most imperiled ecosystems in our region, and throughout the world. While we are tempted to think of plants as basically immobile, passive denizens of our world, carnivorous plants are some of the most obvious examples of the incredibly active role plants take in nature. Stop by and see ours, but more importantly make sure to get out into the wild, visit our protected wetlands, and spot these fantastic plants in their native environments. You won't regret it.