Buzz
Approximately 200 species of fungi are known to capture, kill, and consume tiny creatures, including protozoa, rotifers, small arthropods like tardigrades (“water bears”), copepods, other crustaceans, and nematodes (worms). Over 600 plant species also prey on animals, mostly targeting insects, spiders, other arthropods, and occasionally small vertebrates like frogs, lizards, rats, and birds.
What’s the reason behind this? These fungi and plants thrive in environments with limited nutrients, particularly nitrogen, which is crucial for protein production. Fungi often parasitize or decompose the woody trunks of trees, which are nitrogen-deficient. These plants are typically found in acidic bogs, sphagnum moss, or other nitrogen-poor areas.
While most plants absorb nitrogen through their roots, often with the aid of nitrogen-fixing bacteria, and most fungi gather nutrients from the soil, these meat-eating organisms, dwelling in nutrient-scarce areas, have evolved intricate lures and deadly methods to attract and eliminate their unsuspecting prey, some of which are as ruthless as any medieval torture device.
10. Toilet Bowl Pitcher Plants
The approximately 150 species of tropical pitcher plants from the genus Nepenthes are native to Southeast Asia, the Philippines, Borneo, Sumatra, New Guinea, Sri Lanka, and the eastern coast of Madagascar. Some of these plants grow to impressive sizes and are known to trap and digest a variety of animals, including small vertebrates.
Three species from the mountain rainforests of Borneo can fittingly (though unofficially) be dubbed “toilet bowl pitchers”—Nepenthes lowii, N. rajah, and N. macrophylla. In addition to catching and consuming small animals in their ground-level pitchers, these species also produce modified aerial “toilet pitchers” that grow high up on vine-like stems.
These aerial toilet bowls are uniquely designed to provide a perch for the mountain treeshrew (Tupaia montana), which feeds on the abundant sugary nectar secreted by the pitcher’s lid. To reach the nectar, the shrew must sit directly over the funnel-shaped pitcher opening, which is not slippery like the insect-catching pitchers. While feeding, the shrew often defecates into the pitcher. The next rain will wash the feces into the pitcher, where it is digested, offering a rich source of nitrogen for the plant.
9. Oyster Mushrooms
Oyster mushrooms from the genus Pleurotus are among the most highly sought-after edible mushrooms harvested in the wild by human mycophages (a term from Greek meaning “fungus eaters”). These mushrooms grow on decaying tree trunks, decomposing the wood. The wood is rich in cellulose and lignin but lacks nitrogen, prompting these ingenious fungi to release chemical lures that attract microscopic nematodes as prey.
As the worms crawl onto the fungal hyphae (the thread-like filaments that form most of the mushroom’s mass), the fungus releases toxins from small, matchstick-shaped glands at the tips, paralyzing the worms. The fungus then sends digestive hyphae into the worm’s mouth, which infiltrate its body and slowly digest the defenseless worm from within while it’s still alive.
8. Shaggy Mane (also known as Shaggy Ink Cap)
Another popular edible mushroom (when harvested while still young and fresh) is the nearly worldwide shaggy mane (Coprinus comatus). A member of the ink cap mushrooms, the shaggy mane undergoes autodeliquescence (self-digestion of its spore-bearing gills and cap), turning into a slimy, black liquid within four to six hours after releasing its spores or being collected by a mushroom hunter. To prevent this, it should be quickly sautéed or submerged in a glass of ice water. The time-lapse photographic sequence above illustrates this process.
Nematodes that consume nitrogen-fixing bacteria take in far more nitrogen than they can utilize. These worms excrete most of the excess nitrogen as ammonia, which makes them the primary target of many carnivorous fungi. The shaggy mane preys on two species of plant-attacking nematodes—Panagrellus redivivus and Meloidogyne arenaria. Upon contact with these mushrooms, the worms are struck by tiny, mace-like “spiny balls” at the ends of short hyphal branches. The hollow spikes on these spiny balls pierce the worm’s cuticle (skin), causing its internal pressure to force its body contents outside. This physical damage, coupled with a potent blend of poisons released by the spikes, kills the worm within minutes. The colonizing hyphae then infiltrate the victim’s body through the wounds to digest and absorb its contents.
7. A Fungus That Kills With A Net
Arthrobotrys oligospora is an anamorphic (asexually reproducing) fungus that does not produce fruiting bodies (mushrooms). Instead, it creates a sophisticated three-dimensional adhesive network of sticky, ring-shaped snares that chemically attach to a nematode’s cuticle. Lectin (a protein highly specific to certain carbohydrates) on the surface of the net binds irreversibly with a particular sugar on the cuticle, forming an unbreakable bond. No matter how much the worm struggles, it cannot break these bonds or escape.
By far the most widespread and abundant of all nematode-trapping fungi, A. oligospora thrives in soil, animal waste, and even in both freshwater and seawater, where it feeds on decomposing plant material. It only produces its sticky traps when nematodes are present, which the fungus detects by the worms' scent. The worms secrete a class of chemical pheromones called ascarosides to communicate, regulate their numbers, and find mates. This ensures that the fungus does not waste energy or resources creating its traps unnecessarily.
Different nematode-trapping fungi react to distinct sets of ascarosides based on their preferred nematode species, but the story gets even more complex. Some bacteria produce large quantities of urea, which diffuses through the soil and is absorbed by the fungi. The fungi then convert this urea into ammonia, which triggers the formation of their adhesive nets. The urea also attracts nematodes, whose numbers grow as they consume the bacteria. In turn, the bacteria ramp up their urea production, prompting the fungi to produce even more adhesive traps to control the nematode population. This clever process shows how the bacteria enlist the fungi to defend themselves against the worms! Ultimately, the ammonia released by the bacteria-eating nematodes provides the nitrogen that the fungi seek.
6. A Fungus That Kills With A Lasso
Some nematode-destroying fungi, such as Dreschlerella anchonia, form lassos to capture their prey. These lassos are created by three cells on a specialized hyphal branch, which form a circle that fuses into a tiny, constricting ring, measuring just 0.03 mm in diameter. When a nematode enters the ring, it causes a rupture in the inner walls of the cells, creating a weak spot. The cells' internal osmotic pressure causes water from the outside to rush in, swelling the cells threefold within a fraction of a second. The now-swollen ring tightens around the helpless worm, making escape impossible. The worm’s frantic movements often lead it to be caught in a second noose, as shown above. (Note that the video above incorrectly identifies the fungus as Arthrobotrys oligospora.)
Once the worm is trapped, hyphae emerge from the ring cells, infiltrating the victim’s body and digesting it alive from the inside. An ancient form of nematode-killing fungus that used constricting rings was discovered in 100-million-year-old amber from southwestern France. This fungus lived during the Middle Cretaceous period, a time when giant dinosaurs roamed the Earth and flying reptiles dominated the skies. Unlike its modern counterparts, however, these ancient rings were formed by a single cell instead of three, and were even smaller, just 0.015 mm across.
5. Bladderworts
More than 200 species of the genus Utricularia can be found in freshwater environments (such as ponds and bogs) and in wet, nutrient-poor soils across all continents, except Antarctica. All of these species are carnivorous. While these plants are quite generalized, lacking differentiation in their tissues (other than the flowers), they all capture their tiny animal prey using advanced bladder-trap mechanisms. These remarkable bladder traps are exclusive to this genus of plants.
The bladder creates a partial vacuum by actively pumping water from inside the bladder to the outside, which causes the bladder's sides to collapse. This effectively seals the mouth-like opening, using a combination of specialized flexible tissues and a sticky mucilage that keeps water out. Near the highly sensitive trigger hairs, the mucilage is enriched with sugary carbohydrates that attract prey.
When a tiny copepod, cladoceran (“water flea”), or another suitable prey brushes against the trigger hairs, the seal is broken mechanically, the walls of the bladder spring back into place, and water rushes in through the open mouth, pulling the unfortunate prey inside. This entire process happens in less than 0.001 seconds. Once the trap resets, the water is quickly pumped outside again, and the bladder is ready for the next capture. The prey is then digested by enzymes released within the bladder.
4. Butterworts
Butterworts, belonging to the genus Pinguicula, are part of the Lentibulariaceae family, the same as bladderworts. Instead of using bladder traps, they rely on “flypaper traps.” These traps feature delicate, hair-like pedunculate (stalked) glands on the upper side of their leaves that secrete sticky droplets of mucilage. This shiny substance is believed to attract insects in search of water.
When insects land on the mucilage, they become stuck. The insect’s attempts to escape cause the leaf edges to slowly curl inward, partially enclosing the prey while releasing additional mucilage. Beneath the pedunculate glands, sessile glands produce enzymes that digest the trapped insect. The nutrients released from digestion are absorbed through unique holes in the waxy protective cuticle called cuticular gaps. These gaps are rare in plants and contribute to the butterworts’ vulnerability to dehydration.
The butterwort’s brightly colored flowers, full of sweet nectar, are perched on tall central stems to attract pollinators without risking harm. Their musty-smelling flypaper traps are positioned closer to the ground, effectively luring water-seeking midges, gnats, and other small insects.
3. Carnivorous Bromeliads
Bromeliads are a family of around 3,000 species of ancient plants that are closely related to grasses and sedges, predominantly found in the tropical and subtropical Americas, with just one species in Africa. This family includes the pineapple, Spanish moss, and many epiphytic species native to the tropical cloud and rain forests of Central and South America. Many of these plants live high up in the trees, absorbing carbon dioxide for photosynthesis directly from the air. The leaves of the so-called “tank bromeliads” form overlapping bases that collect water, which provides a safe haven for tropical tree frogs to lay their eggs and raise tadpoles.
Some bromeliads are also common succulent plants found in the deserts of the Southwestern United States. While it seems they are perfectly suited to develop carnivorous traits, particularly since insects often fall into their water pools and drown, only three species from two genera (Brocchinia and Catopsis) are actually carnivorous. These species feature specialized upright leaves that store permanent water pools. Their leaves are coated with a powdery substance that reflects ultraviolet light, attracting UV-sensitive beetles and other insects. The attraction is further enhanced by nectar-like secretions that the insects feed on. Insects that land on the powdery surface slip and fall into the water, where they are digested by the plant’s enzymes and bacteria living within the pools.
2. Insect-Eating Pitcher Plants
Pitcher plants craft their leaves into pitfall traps—tall, hollow, trumpet-shaped vessels filled with a mixture of acidic water and a surfactant, a detergent-like substance. These pitcher leaves also mimic insect-attracting flowers, gradually turning a purple-red hue as they accumulate anthocyanins, the pigments responsible for the vivid colors of autumn foliage. Near the trap’s entrance, the leaves secrete a sweet nectar that lures flies, ants, beetles, and other insects.
The inner walls of the pitcher’s upper section are coated with a slick wax that causes any insect that lands there to slip into the water below. If the insect somehow escapes from the trap, it crashes into the steep walls of the trumpet-shaped tube, which then sends it back into the liquid. The wetting agent ensures the insect cannot escape, causing it to sink to the bottom where it is slowly digested by the acidic liquid, with the help of digestive enzymes produced by bacteria in the mixture.
Around a dozen species of the genus Sarracenia thrive in the acidic bogs of eastern North America, with possibly twice as many species from the genus Heliamphora found in South America. Additionally, a single species of the genus Nepenthes is native to northern California and Oregon.
1. Sundews
Sundews employ far more complex flypaper traps than butterworts, with over 180 species of the genus Drosera belonging to a distinct family (Drosseraceae). Their prominent glandular leaf hairs (which give sundews their name) are much larger and more noticeable than those of butterworts, yet they function in the same way. The glands secrete nectar to attract insects, along with sticky mucilage and digestive enzymes to ensnare and break down the prey.
Insects such as flies that land on the leaves to sip the nectar get ensnared by the sticky glue. Other specialized leaf hairs then activate, and the leaf itself may begin to curl over the prey, trapping it further. This entire process unfolds slowly, often taking hours, but once the insect is stuck, there's no escape! Subsequently, enzymes are released from the leaf hairs, which gradually digest the trapped insect.
