A recent tour of the fish ladders in the Somes Pond watershed led me to the mouth of Somesville Brook. Here a marsh extended up to the edge of the local cemetery. Our guide pointed out the pitcher plants in full bloom. The brilliant red blossoms drooping on long, wispy stems seemed oddly serene for such vicious organisms.
Bogs supports some of the most interesting plants in the U.S., including the carnivorous northern pitcher plant (Sarracenia purpurea), which compensates for the lack of nutrients in bog soils by capturing insects in its leaves and and digesting them. It has been widely assumed that the prey-trapping mechanism featuring a deep cavity with a pool of liquid at the bottom, known as a pitfall trap, evolved from rolled leaves selection pressure favoring more deeply cupped leaves. Insects are attracted to the cavity formed by this cupped leaf, and once inside, cannot crawl back up the slippery, grooved sides of the trap. Trapped insects drown in a small puddle of liquid in the bottom of the cavity, their bodies gradually dissolving and feeding the plant. The insects’ dead bodies may also be digested by mutualistic insect larvae, whose excrement provides nutrients that the plant can absorb.
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