Sarraceniaceae is a family of carnivorous pitcher plants native to North and South America. These low-growing perennial herbs are notable for their modified pitcher-like leaves, which serve as pitfall traps to ensnare and digest insects and other small prey. They derive their common name from their hollow tubular leaves, which can take the form of a trumpet, a pitcher, or an urn (Encyclopaedia Britannica, 2015).
The carnivorous pitcher plants of the Sarraceniaceae are generally thought to have developed deceptive mimetic systems, advertising visual and olfactory signals, which provide them with the ability to deceive insects by attracting them into traps (Joel, 1988). The leaves are adapted to function like flowers in attracting insects: they are flowerlike in their striking colour patterns and shapes, and, during their active period in the summer, they exude nectar containing fructose, which is highly attractive to some insects. These leaves passively capture prey that are lured to the leaf’s mouth by its glistening surfaces or unusual colouration and transparent patches. Besides having flower-like leaves, all members of Sarraceniaceae produce flowers that are showy and have an agreeable scent. If an insect or other organism falls into the pitcher, stiff downward-pointing hairs and slippery walls prevent it from crawling back out. Exhausted, the animal eventually drowns in the liquid at the bottom of the pitcher. Protein-digesting enzymes and bacteria break down the insect’s body, allowing nitrates and other useful nutrients to be absorbed by the plant to supplement the poor soil conditions of its environment. The nodding flowers are insect-pollinated and are usually borne on long stalks to keep the pollinators away from the deadly pitchers (Encyclopaedia Britannica, 2015). Thus, these flowers have developed a separate system for attracting pollinators and prey.
Little is known about the evolutionary experimentation that led to the development of these carnivorous tactics, but other families of carnivorous plants have developed similar strategies in response to similar soil conditions (Schwaegerle and Schaal, 1979). New phylogenetic analyses are beginning to reveal the evolutionary relationships and the amount of convergent evolution present in the carnivorous plants, but the amount of research done remains somewhat limited (Ellsion and Gotelli, 2001).
Ellison, EM and Gotelli, NJ, 2001, Evolutionary ecology of carnivorous plants, Trends in Ecology and Evolution, vol. 16, no. 11, pp. 623-629.
Encyclopaedia Britannica, 2015, Encyclopædia Britannica Online, Sarraceniaceae. Retrieved 19 April, 2015, from http://www.britannica.com/Sarraceniaceae
Joel, DM, 1988, Mimicry and mutualism in carnivorous pitcher plants (Sarraceniaceae, Nepenthaceae, Cephalotaceae, Bromeliaceae), Biological Journal of the Linnean Society, vol. 35, pp. 185-197.
Schwaegerle, KE and Schaal, BA, 1979, Genetic Variability and Founder Effect in the Pitcher Plant Sarracenia purpurea L., Evolution, vol. 33, no. 4, pp. 1210-1218.
Photo from Learn About Nature retrieved 19 April, 2015 from http://www.carnivorous--plants.com/pitcher-plant.html