Nepenthes spp. (monkey cups)
Nepenthes comprise about 90 species occupying tropical habitats in Australia,
Madagascar, Papua New Guinea, the Seychelles, Southeast Asia and Sri Lanka.
The pitcher trap of Nepenthes contains a fluid of the plant's own production, which
may be watery or syrupy and is used to drown the prey. Nepenthes usually produce
two types of pitchers. Large lower traps, which typically sit on the ground, grow
near the base of the plant, while the upper pitchers may be smaller, colored
differently, and have different features than the lower pitchers. These upper
pitchers usually form as the plant reaches maturity and the plant grows taller. To
keep the plant steady, the upper pitchers form loops in their tendrils, allowing them
to wrap around nearby support. In some species, different prey may be attracted by
the upper and lower pitchers. Nepenthes prey usually consists of insects, but the
largest species may occasionally catch small vertebrates, such as rats and lizards!
Dionaea muscipula (Venus flytrap)
The Venus Flytrap grows in wet sandy and peaty soils in nitrogen-poor
environments, such as bogs and wet savannahs. Small in stature and slow growing,
the Venus flytrap tolerates fire well, and depends on periodic burning to suppress
its competition. Fire suppression threatens its future in the wild. The Venus flytrap
is found natively only in North and South Carolina in the United States, specifically
within a 100 mile radius of Wilmington, North Carolina.
The leaf blade is divided into two regions: a flat, heart shaped photosynthetic
petiole, and a pair of terminal lobes hinged at the midrib, forming the snap trap that
is the true leaf. The upper surface of these lobes contains red anthocyanin pigments
and their edges secrete mucilage. The lobes exhibit rapid plant movements,
snapping shut when stimulated by prey. The trapping mechanism is tripped when
prey items stumble against one of the three hair-like trichomes that are found on
the upper surface of each of the lobes. The trapping mechanism is so specialized that
it can distinguish between living prey and non-prey stimuli such as falling
raindrops: two trigger hairs must be touched in succession or one hair touched
twice, whereupon the lobes of the trap will snap shut in about 0.1 seconds.
Drosera spp. (sundews)
Various species of Drosera, which vary greatly in size and form, can be found
growing natively in bogs and nutrient poor soils on every continent except
Antarctica.
Sundews lure, capture, and digest insects using stalked mucilaginous glands
covering their leaf surface. All species of sundew are able to move these glandular
tentacles in response to contact with digestible prey. The tentacles are extremely
sensitive and will bend toward the center of the leaf in order to bring the insect into
contact with as many digestive glands as possible.
Pinguicula spp. (butterworts)
The butterworts use sticky, glandular leaves to lure, trap, and digest insects. Of the
roughly 80 currently known species, 12 are native to Europe, 9 to North America,
and the rest are found in northern Asia, South and Central America and southern
Mexico. In general, butterworts grow in nutrient poor, alkaline soils. Some species
have adapted to other soil types, such as acidic peat bogs, soils composed of pure
gypsum, or even vertical rock walls. A few species are epiphytes. Each of these
environments is relatively nutrient poor, allowing butterworts to compete for space.
Darlingtonia californica (cobra lily or cobra plant)
The cobra lily is native to Northern California and Oregon, where it grows in acidic,
nutrient-poor bogs and seeps with cold running water.
The cobra lily has two unique characteristics that differentiate it from the other
West Coast pitcher plants of the genus Sarracenia. First, it does not trap rainwater in
its pitcher. Instead, it regulates the level of water inside physiologically by releasing
or absorbing water into the trap that has been pumped up from the roots. Second,
unlike some other pitcher-plants, its leaves don't produce any digestive enzymes.
The cells that absorb nutrients from the inside of the pitcher are the same as those
on the roots that absorb soil nutrients. Instead, the California pitcher plant relies on
symbiotic bacteria and protozoa to break down the captured insects into easily
absorbed nutrients.
In addition to the lubricating secretions and downward-pointing hairs used by all
pitcher plants to force their prey down into the trap, this species carefully hides the
tiny exit hole from trapped insects by curling it underneath the “roof” of the leaf trap
and offering multiple translucent false exits (like skylights). Upon trying many times
to leave via the false exits, the insect will tire and fall down into the trap.
Sarracenia spp. (American pitcher plant)
Sarracenia species are indigenous to the eastern seaboard, Texas, the Great Lakes
area and southeastern Canada, with most species occurring only in the southeastern United States. Sarracenia usually inhabit permanently wet locations with a
low pH whose nutrients, particularly nitrates, are continuously leached away by
water or made unavailable by the low pH.
Sarracenia leaves have evolved into a funnel-shaped pitcher trap in order to catch
insects and digest them with proteases and other enzymes. Insects are attracted by
a nectar-like secretion on the lip of pitchers, as well as a combination of color and
scent. Slippery footing at the pitchers' rim, aided in at least one species by a narcotic
drug lacing the nectar, causes insects to fall inside, where they die and are digested
by the plant as a nutrient source.
Cephalotus follicularis (Albany pitcher plant, Western Australian pitcher
plant)
The Albany pitcher plant occurs in southern coastal districts of Southwest Australia.
Its habitat is on moist peaty sands found in swamps or along creeks and streams.
The pitcher trap of the species is similar to that of other pitcher plants. The lip
ringing the entrance of the trap has a spiked arrangement that allows the prey to
enter but hinders its escape. The lid over the entrance, the operculum, prevents
rainwater entering the pitcher and thus diluting the digestive enzymes inside.
Insects trapped in the digestive fluid inside the pitcher are digested and absorbed by
the plant. The operculum has translucent cells that confuse insect prey, as they
appear to be patches of sky.