The leaves are so weird and wonderful that people often don't notice the flower stalks that stick up a foot above the leaves, the buds being dark maroon balls. These do make seeds with cooperation from bumblebees, but the plants are perennial, making up to eight new leaves every year. The most effective leaves are under 50 days old.
Bogs are too wet, acidic and cold for bacteria to thrive and break down dead material for reuse, so pitcher plants use enzymes and bacteria to "digest" the insects they attract and then trap. Lip edge producing nectar, a numbing solution and a sweet odor (hmm, maybe that is where the ever present and mysterious sweet smell of a bog comes from); veins reflecting UV light; stiff downward pointing hairs; and smooth waxy sides down below all combine to do the dirty deed. On one trip I watched a tan moth feeding excitedly around the lip, but I didn't stay to see the end of the story!
As in all nature, it's not a one way street. Fifty families of insects use pitcher plants, eating them directly as caterpillars; or in the case of many flies, their larvae (let's face it-maggots) use trapped insects in different stages of decomposition.
One mosquito larva lives in the pitcher water happily, eating the debris, using dissolved nutrients, and freezing solid in the winter. Aquatic mites use the bacteria, protozoa, nematodes, and rotifers that share the pitcher's contents. All of these of course have to be resistant to the enzymes that kill other creatures. A solitary wasp cuts a hole in the bottom of a leaf so the water drains out, stuffs it with grass in which it lays eggs, then provides sting-paralyzed caterpillars for its larvae to eat. A spider spins a web to catch insects before they fall in, but it sometimes falls in itself. Read John Eastman's Swamp and Bog for more stranger than fiction stories.
I have found through the years that on sunny days there are very few biting bugs in bogs. In researching this column I came across a study where 85% of the trapped insects were black flies. Three cheers for those pitcher plants! And for the cranberries decorating the bogs this time of year.