The Carnivorous Pitcher Plants

On the last day of my trip to the north woods along Lake Huron, I discovered these pitcher plants in a bog.

This plant is about the size of a large pizza pan.

Perhaps these are not as spookily exciting as a Venus Fly Trap, but they are still a very interesting carnivorous plant.  Here is a run down of the facts you might find interesting:

• As carnivorous plants, there is a prey-trapping mechanism.  The mechanism found in these pitcher plants is a deep cavity filled with liquid.  The "well" is actually a modified leaf.
• Flying or crawling insects are attracted to the deep wells by either anthocyanin pigments (not really seen in my photo above) or by the bribe of sweet nectar.

• The insect crawls into the "pitcher" but cannot easily escape.  The walls of the pitcher may be slippery or grooved in a way that prevents the insect from escaping.
• The insect drowns in the fluid contained in the pitcher.  The body of the insect is gradually dissolved either by bacterial action or by digestive enzymes that are produced by the plant itself.

• The body of the insect is reduced to a soup of amino acids, peptides, phosphates, ammonia and urea.  This is how the plant obtains its mineral nutrients, especially nitrogen and phosphorus.
• My students often mistakenly think that the carnivorous plants "eat the insects" as a source of food.  These are true plants and are photosynthetic.  These plants make their own food in the form of sugars using the energy from the sun, just as all photosynthetic plants do.  However, these plants live in locations where the soil is poor in minerals.  Since these plants cannot obtain minerals from the soil, the insect is the source of mineral nutrients that are required by the plant.

The photographs you see above are pictures of the plants I found.  To give you an idea of the variety that exists in these plants, here are a couple of photos of pitcher plants of different species.  These are public domain photos, and were not taken by me.

I thought it would be great fun to try to grow pitcher plants and keep them in my classroom at school.  This is the very sort of thing that my biology students love!  Here is a great article on how to grow the pitcher plants if you are interested.

Finally, I absolutely love the BBC series by David Attenborough called "The Private Life of Plants".  Here is a short, 4-minute video segment from that series about the pitcher plants.  My students love this video!

Have fun teaching!