Typically plants fall at the bottom of the food chain, eaten by almost all other creatures. The exceptions to the rule are the carnivorous plants, displaying a role reversal from prey to predator. These plants have developed evolutionary mechanisms to trap insects and digest them in order to survive in the nutrient poor habitats they grow in. There are about 600 species of carnivorous plants belonging to 7 families and 15 genera. Carnivory in plants are exhibited by two types of trapping mechanisms – active trapping and passive trapping. The Venus fly trap (Dionaea muscipula) fall under the active trapping category and the pitcher plants (Nepenthes spp. and Sarracenia spp.) fall under the passive trapping category.
Most tropical botanists and horticulturists have heard of mice being trapped in Nepenthes pitchers in the rainforests of Malaysia and Borneo. This past week our greenhouse/conservatory team got to actually witness it firsthand. At our Chatfield greenhouses where our back-up collections are now located, staff found a mouse trapped in the pitcher of a Nepenthes truncata. Native to the lowland rainforests of the Philippines, the pitchers of N. truncata are among the largest for this genus.
The pitchers of the pitcher plants usually have bright coloration and sweet nectar around the rim, which attract unsuspecting insects and other small prey to them. When the prey slips and falls into the pitcher, it falls into a pool of digestive fluid. The downward pointing hairs along the sides of the pitcher prevent the prey from climbing out and it drowns in the fluid. These amazing plants are now easily available in cultivation with many hybrids developed. At Denver Botanic Gardens, in addition to Nepenthes, we have a large collection of other carnivorous plants. Please visit the Fly Trap Feast in the Oak Grove to see some of these amazing plants.