Mushrooms: How Do They Feed?

Mushrooms are the fleshy fruit of an underground fungus, and while they have historically been considered primitive plants, they are now known to be biologically distinct from plant- and animal-derived foods. Fungi feed by absorbing nutrients from their environment, and different types of mushrooms have different food sources. Some mushrooms are parasitic and feed on living organisms, while others are cultivated on straw and hardwood sawdust. Mushrooms are a source of nutrition for many organisms, including birds, mammals, insects, and humans, who consume them for their unique health benefits.

Mushrooms are fungi, not plants, animals or bacteria

Mushrooms are fungi, a kingdom separate from plants, animals, or bacteria. Fungi were once considered primitive plants due to their similar appearance, cell walls, and immobility. However, scientists now recognize unique chemical, physical, and genetic traits that set fungi apart. One major difference is how they obtain nutrition. Unlike animals, fungi cannot ingest their food, and unlike plants, they do not make their own food through photosynthesis. Instead, they feed by absorbing nutrients from their environment.

Fungi accomplish this by growing through and within their food source, which can include wood, cheese, soil, or flesh. They secrete digestive enzymes that break down large organic molecules into smaller, simple molecules that can be easily absorbed by the fungus. This process is called fungivory or mycophagy. Many different organisms, including birds, mammals, insects, plants, amoebas, gastropods, nematodes, bacteria, and other fungi, have been recorded consuming fungi.

While most of these organisms only consume fungi as part of their diet, some are fungivores, meaning they exclusively eat fungi. Certain insects, such as ambrosia beetles, farm ambrosia fungi inside trees and feed on them. Some species of ants in the rainforests of Southeast Asia have been found to have a diet consisting almost entirely of mushrooms. Among mammals, at least 22 species of primates, including humans, bonobos, gorillas, and lemurs, are known to feed on fungi, although it typically makes up a small part of their diet.

Fungi themselves can also be parasitic, feeding on living organisms without giving anything in return. Parasitic mushrooms can have hosts that are not only plants and trees but also insects. For example, the caterpillar fungus (cordyceps sinesis) infects and kills a specific species of caterpillar before growing out of the dead insect. Other mushrooms, like elm oyster mushrooms, are considered both parasites and saprotrophs, as they grow on living trees but can also be cultivated on dead tissue.

Parasitic mushrooms feed on hosts, but don't give anything back

Mushrooms are the fleshy fruit of an underground fungi. Fungi, which include mushrooms, are not plants, animals, or bacteria but belong to a separate kingdom of their own. Fungi are unique in the way they obtain nutrition.

Parasitic mushrooms are the fruiting bodies of parasitic fungi that get the nutrients they need to survive from a living host. Parasitic fungi invade and feed on other living organisms, including plants, animals, insects, and other fungi. They extract nutrients from the organism's living tissue, often causing damage and sometimes killing the host. Parasitic mushrooms feed on their hosts but do not give anything back. They do not limit themselves to plants and trees. Some parasitic mushrooms, like the caterpillar fungus, use insects as hosts. Over time, parasitic fungi will completely infect the host plant or insect, causing it to die.

Most parasitic fungi do not produce mushrooms, but a few species do. Many of these use more than one feeding method, and most mushroom-producing parasitic fungi are also saprotrophic, meaning they decompose dead and decaying organic matter. Few true parasitic mushrooms are edible, but some semi-parasitic species produce well-known gourmet mushrooms. Lion's mane mushrooms, for example, are both parasites and saprotrophs. They are edible and medicinal, with teeth instead of gills. Chaga mushrooms are another example of parasitic mushrooms with medicinal compounds. They are often ground into a powder and used to make tea.

While parasitic relationships only benefit the fungi, mycorrhizal fungi form mutually beneficial relationships with their hosts. Mycorrhizal mushrooms have a symbiotic relationship with trees and plants. They use their underground network of mycelium to interact with the roots of the plants, providing them with extra nutrients and moisture in exchange for simple sugars produced through photosynthesis.

Elm oyster mushrooms grow on living trees, but can be cultivated on straw

Elm oyster mushrooms (Hypsizygus ulmarius) are parasitic saprotrophs, typically growing on living elm trees. They are often found high up on the trunks of trees, growing from knots, wounds, and branch scars. Elm oyster mushrooms can also be found on dead and decaying trees. These mushrooms are usually white to beige in colour, with a tough, curved stem and a round cap. They are easy to identify and have no poisonous lookalikes, making them ideal for beginner foragers.

While elm oyster mushrooms are typically found on living trees, they can also be cultivated on straw and sawdust blocks. They are excellent for indoor cultivation as they are hardy, fast-growing, and can tolerate high levels of carbon dioxide. When grown indoors, they are often found on bags of straw or hardwood shavings.

To cultivate elm oyster mushrooms, it is recommended to use pasteurized straw or amended sawdust blocks. They can also be grown outdoors on elm or beech logs. For first-time mushroom growers, it is advisable to start with a ready-to-grow colonized block of substrate.

Mushrooms, including elm oyster mushrooms, are unique in that they are not plants, animals, or bacteria but belong to their own separate kingdom. They are the fleshy fruit of an underground fungus. Fungi, including mushrooms, obtain their nutrition from the environment, breaking down large organic molecules into smaller ones that they can absorb. Some mushrooms, like elm oyster mushrooms, are parasitic and feed on their hosts without giving anything back. However, it is unclear whether elm oyster mushrooms feed on living or dead tissue, and they may instead benefit their host trees by improving pest resistance and nutrient absorption.

Oyster mushrooms can feed on over 150 agricultural byproducts

Mushrooms are unique because they are not plants, animals, or bacteria but belong to a separate kingdom. They are the fleshy fruit of an underground fungus. Fungi differ from plants in how they obtain nutrition. Some mushrooms are parasitic, feeding on a host, which can be a plant, tree, or insect, without giving anything back. Other mushrooms are saprotrophs, which feed on dead organic matter.

Oyster mushrooms (Pleurotus species) are a type of fungus that can feed and grow on over 150 different agricultural byproducts. They are the second most commonly grown mushroom type in the world, after the white button mushroom. They are prized for their taste, aroma, flavour, nutritional benefits, and medicinal properties. They are also versatile, thriving in both tropical and temperate regions without requiring complex controlled environmental conditions for growth. They can be cultivated on straw and hardwood sawdust.

Oyster mushrooms are particularly good at breaking down lignocellulosic materials, which are agricultural wastes that include cellulose, hemicellulose, and lignin. These materials offer vital nutrients for mushroom growth. Employing these agricultural by-products as a substrate for oyster mushroom cultivation is a sustainable approach to waste reduction and the production of nutritionally enriched food.

Oyster mushrooms are also sought after as functional food because they contain high levels of protein, fiber, vitamins B complex, C and D2, as well as minerals like potassium, phosphorus, selenium, zinc, and essential amino acids. They are also easy to grow at home, as they can feed on a wide range of substrates.

Fungi are an important part of the southern cassowary's diet

The southern cassowary (Casuarius casuarius) is a large, solitary bird native to Australia. It is an omnivore, with a diet consisting primarily of fallen fruit and seeds. However, fungi are also an important part of the southern cassowary's diet.

Cassowaries are opportunistic feeders, and their diet includes a variety of foods such as invertebrates, small vertebrates, and carrion. Fungi are among the prey items that cassowaries find at ground level, along with insects and small animals. Bracket fungi have been found in their droppings throughout the year, and it is likely that they also consume other types of fungi.

Southern cassowaries play an important role in the ecosystem by dispersing the seeds of many tropical plants. They swallow fruits whole, and the seeds pass through their digestive system and are deposited intact in their droppings, sometimes at great distances from the parent tree. This helps to propagate and spread various plant species.

Cassowaries have a strong preference for certain types of fruit, with documented sources including the families Lauraceae, Myrtaceae, Elaeocarpaceae, and Arecaceae. They are also known to consume fruit from at least 75 different plant species in Australia. While fungi are not their primary food source, they do provide a supplementary source of nutrition for these large birds.

Fungi are a comparatively rare food source in the tropical rainforests inhabited by southern cassowaries, which may make them a challenging food to find for some species. However, cassowaries have a diverse diet and are capable of consuming a wide range of foods, including fungi, which contributes to their overall nutrition and health.

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