What are
carnivorous plants?
From Darwin to bladder traps: how plants evolved into predators, and what exactly makes them carnivorous
Plants that catch and eat insects – it sounds like something out of a horror movie, but carnivorous plants are one of the most fascinating groups in the plant kingdom. It was none other than Charles Darwin who first scientifically proved in 1875 that these plants are indeed carnivorous. Since then, more than 600 to 1000 species have been described, spread across multiple plant groups that independently developed the same strategy.
What makes a plant carnivorous?
Not every plant that happens to catch an insect is also carnivorous. A rose on which a fly dies is not a carnivorous plant. To be considered truly carnivorous, a plant must meet three cumulative conditions:
This adaptation is no coincidence: carnivorous plants almost always grow on nutrient-poor, wet soils such as bogs, marshes, and rock faces with rainwater. Nitrogen and phosphorus are scarce in these environments; by catching prey, they compensate for this deficiency.
Five trapping methods
Carnivorous plants have evolved independently multiple times, and this is reflected in the diversity of trapping mechanisms. There are five main types:
Leaves are covered with sticky, glue-like droplets that hold small insects as soon as they make contact. In some species, like Drosera, the leaf can slowly wrap around the prey for better digestion. This is the most common trapping method in the carnivorous plant world.
Insects are attracted by color or scent and fall into a pitcher from which they cannot escape. In Sarracenia, downward-pointing hairs create this effect; in Nepenthes and Cephalotus, there is a large amount of digestive fluid in the pitcher. A persistent myth: the pitchers do not close themselves — they are always open.
Prey do not fall into the trap but walk into it on their own. Small translucent windows at the top of the trap disorient insects: they fly towards the light, but that is not the exit. Once inside, they become confused and sink deeper into the trap.
The best-known and most spectacular method. On each side of the leaf are three trigger hairs. If two hairs are touched within 20 seconds, the trap snaps shut. If there is actually something inside, further movement stimulates the plant to fully close the trap and release digestive juices. This prevents the plant from wasting energy on, for example, raindrops.
The most ingenious method. Small underwater bladders are filled with air as the plant actively pumps out fluid — creating a vacuum. As soon as prey touches a trigger hair, the trapdoor springs open, and the surrounding water with the prey is sucked in within milliseconds. Utricularia (bladderwort) also occurs in the Netherlands and Belgium, in the same areas as sundews.
Want to know more or get started yourself?
On our website, you'll find care tips for each species and a fully cultivated assortment ranging from hardy Sarracenia to tropical Nepenthes.
Questions about carnivorous plants?
Whether you're just starting out or have been growing for years, feel free to send a message to killian@dupontflora.com. We're happy to help you based on 15 years of our own growing experience.
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