Sarracenia Nepenthes - faculty.weber.edu

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2 Carnivorous Plants
• all known carnivorous plants are flowering plants
• there are ~300,000 species of flowering plants
• ~ 450 species of carnivorous plants are known
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3 Carnivorous Plants
use modified leaves to practice carnivory

leaf modifications allow carnivorous plants to
• attract prey (small animals like insects)
• trap prey
• digest their prey (polymers → monomers)
• absorb monomers
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4 ecosystem – trophic levels
• Producers

– autotrophs
– manufacture their own food by photosynthesis or chemosynthesis
• Consumers
– heterotrophs
– get food by eating producers or other consumers
– their “leftovers” still have nutritional value
• Decomposers
– heterotrophs
– get food by eating the remains of producers or other consumers
– break down organic matter to a form from which elements can be re-assimilated by the

producers
5 two main trapping strategies

• active trappers move to catch prey
– Venus flytrap
– waterwheel
– bladderwort

• passive trappers use pitfalls and sticky secretions to catch prey
– pitcher plant
– sundew
– butterwort

6 Venus Flytrap
7 Venus Flytrap

• Active trapper
• Insect touches
trigger hairs
on leaf surface.
8 Venus Flytrap cont.
• The cells on the underside of the leaf rapidly enlarge. This causes the leaf to quickly fold

shut on the insect.
• As the insect struggles, the trap tightens. Digestion begins.
• Once the insect has been digested, the cells on the upper side of the leaf grow. This

growth opens the leaf again and resets the trap.
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9 Waterwheel Plant (Aldrovanda)

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• Active trapper
• Aquatic
• Rapid (< 0.5 sec) leaf movement to snap shut on prey

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• prey touches the trigger hairs
• the trap snaps shut
• water is removed; trap narrows
• digestive begins
11 Bladderwort (Utricularia)
12 Bladderwort
• largest genus of carnivorous plants, >200
• active trapper
• primarily aquatic
• bladder is under tension
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13 Bladderwort
• Aquatic critter (usually insect larva) brushes against trigger at mouth of the bladder.
• The bladder opens, a vacuum pulls in the larva, along with a lot of water.
• Once the larva is digested, the water is removed from the bladder, and the trap is reset.
14 Pitcher Plants
15 North American Pitcher
(Sarracenia)
• Passive trapper.
• The leaf forms a cone.
• Colorful “flag” and nectar attract insects.
• Possibly a narcotic in the nectar.
• Downward pointing hairs make is difficult for insects to walk up the sides of the pitcher.
• A solution of digestive enzymes is at the base of the cone. Also present: bacteria, insect

larvae
• Insects fall into the cone, drown, and are digested.
16 Tropical Pitcher Plants
(Nepenthes)
• Tip of the leaf forms a tendril; tip of the tendril forms the trap.
17 Nepenthes attenboroughii
• Some pitchers are quite large, holding up to a liter of liquid.
18 Cobra Lily (Darlingtonia californica)
• Insects attracted by scent; can’t find the exit once they enter the pitcher
• Does not seem to secrete its own digestive enzymes; relies on bacteria and larvae
19 Sundew
• Passive trapper.
• Sticky, stalked glands cover the leaves. Insects get stuck and can't get away.
• Slowly, the stalked glands fold over the insects. Eventually, the entire leaf can curl around

the insect.
• By having the leaf in close contact with the insect, there is more efficient digestion and

uptake of nutrients.

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21 Butterwort
• Passive trapper.
• Flat sticky glands on leaf surface. Insects get stuck.
• Slowly, the leaf can cup around the insect for improved digestion and nutrient uptake.

22 Features of Carnivorous Plants

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• The carnivorous plants use a variety of features to attract insects: color, scent, nectar
reward. These are the same features found in flowers to attract pollinators.

23 Features of Carnivorous Plants
• Glands for secretion and absorption ==> not unique to carnivorous plants.
• sticky secretions

24 Features of Carnivorous Plants
• Leaf modifications: common among plants. Even the parts of flowers (petals, etc.) are
modified leaves.

25 Plants with “Pitchers”
26 Features of Carnivorous Plants

• Rapid movements
• Some plants, like the sensitive plant (Mimosa), have rapid leaf movements that startle

insects.
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27 Features of Carnivorous Plants
• The plant features found in carnivorous plants aren't unique to them.
• However, the carnivorous plants have put the features together in such a way that they can

attract, catch, digest, and/or absorb prey.

28 Why?
• Does this make carnivorous plants consumers? No. They have no trouble doing
photosynthesis.
• Where do you find carnivorous plants? Mineral poor soils. Most plants can't live in these
habitats. Carnivorous plants can because they can use insects as source of mineral
nutrients, especially N.

29 Are there any
carnivorous plants in Utah?

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common bladderwort (Utricularia vulgaris or Utricularia macrorhiza Le Conte)

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33 For More Information
http://www.sarracenia.com/cp.html
web site authored by Barry Rice
Photo Gallery of Carnivorous Plants
Carnivorous Plants FAQ

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36 Are there any vegetarian carnivorous plants?

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