Did you know both Woodward Reservoir and Lake Ninevah are home to several carnivorous aquatic plant species? They use various methods to capture their prey including pitfall traps, flypaper traps, and snap traps. One of those species is the Common Bladderwort, (Utricularia vulgaris), which is found in all of the New England states and native to North America. It uses a method of sudden suction to catch its prey. Unlike most plants that receive nutrients from the ground in which they are growing, the bladderworts do not have roots. Instead, they have tiny sacs of air called bladders that collect water and trap small aquatic organisms such as water fleas, mosquito larvae, or isopods that they then use as food. The size of the bladders varies depending on the species but the diameters can range from 1/5 of an inch to 1/100 of an inch. The outside of the bladders of the common bladderwort is covered in tiny hairs and when something brushes up against the hairs, the bladder opens. Other species of this genus lack these hairs outside of the bladder. There is still speculation as to what attracts prey to the bladders. Some suggest that glands outside the bladder door secrete a sugary substance that entices prey to approach. Once the bladder door opens, water and occasionally a small aquatic organism is sucked into the bladder through a vacuum like mechanism and the bladder then closes abruptly. This whole process takes about 3 milliseconds! The food is then digested in the bladder with the help of enzymes and bacteria. Digestion can last between fifteen minutes to two hours depending on the size and type of the prey. Once digestion is complete, the water that was sucked into the bladder is released. This process of the prey triggering a response is comparable to another carnivorous plant that you may be more familiar with, the Venus Fly Trap.
In general, bladderworts are found worldwide except Antarctica. There are fourteen species of bladderwort in the Northeastern United States with the common bladderwort and the horned bladderwort (Utricularia cornuta) being the most common. The Common Bladderwort is easily identified by its bright yellow flower that sticks out of the water and the small bladders visible on the leaves. Some have compared their small yet beautiful flowers to snapdragons due to their unique shape. This flower can be pollinated to produce seeds, but nutrients and overall health of the plant is supported by the prey that is sucked into the bladders. The leaves of the bladderwort can be seen floating or submerged and are easy to overlook when the plant is not in flower. The horned bladderwort can occasionally be found growing in mud or peat and more commonly in bogs, fens, and open waters. It has a distinctive horn shape that hangs from its yellow flower and the bladders do not have tiny hairs that hang in front of the door like the common bladderwort. The common bladderwort tends to have larger bladders than the horned bladderwort. New England is home to rare bladderwort species as well. The next time you are out paddling or swimming on a local body of water such as Lake Ninevah or Woodward Reservoir, be sure to keep your eye out for the common bladderwort. If you are lucky, you may be able to watch their magic prey catching mechanism in action!