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Fungivory or mycophagy is the process of organisms consuming
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
. Many different organisms have been recorded to gain their energy from consuming fungi, including birds, mammals, insects, plants, amoebas, gastropods, nematodes, bacteria and other fungi. Some of these, which only eat fungi, are called fungivores whereas others eat fungi as only part of their diet, being
omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nu ...
s.


Animals


Mammals

Many mammals eat fungi, but only a few feed exclusively on fungi; most are opportunistic feeders and fungi only make up part of their diet. At least 22 species of
primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter includin ...
, including
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s,
bonobo The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee and less often the dwarf chimpanzee or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus '' Pan,'' the other being the comm ...
s,
colobine The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications split ...
s,
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four ...
s,
lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madagas ...
s,
macaques The macaques () constitute a genus (''Macaca'') of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. Macaques are principal ...
,
mangabey Mangabeys are West-African Old World monkeys, with species in three of the six genera of tribe Papionini. The more typical representatives of ''Cercocebus'', also known as the white-eyelid mangabeys, are characterized by their bare, upper eye-l ...
s,
marmoset The marmosets (), also known as zaris or sagoin, are 22 New World monkey species of the genera ''Callithrix'', ''Cebuella'', ''Callibella'', and ''Mico''. All four genera are part of the biological family Callitrichidae. The term "marmoset" is ...
s and
vervet monkey The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...
s are known to feed on fungi. Most of these species spend less than 5% of the time they spend feeding eating fungi, and fungi therefore form only a small part of their diet. Some species spend longer foraging for fungi, and fungi account for a greater part of their diet; buffy-tufted marmosets spend up to 12% of their time consuming sporocarps, Goeldi’s monkeys spend up to 63% of their time doing so and the
Yunnan snub-nosed monkey The black-and-white snub-nosed monkey (''Rhinopithecus bieti''), also known as the Yunnan snub-nosed monkey, is a large black and white primate that lives only in the southern Chinese province of Yunnan, where it is known to the locals as the Yun ...
spends up to 95% of its feeding time eating
lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.poison Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...
s to deter animals from feeding on them: even today humans die from eating poisonous fungi. A natural consequence of this is the virtual absence of obligate
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...
fungivores, with the
diprotodont Diprotodontia (, from Greek "two forward teeth") is the largest extant order of marsupials, with about 155 species, including the kangaroos, wallabies, possums, koala, wombats, and many others. Extinct diprotodonts include the hippopotamus-sized ...
family Potoridae being the major exception. One of the few extant vertebrate fungivores is the
northern flying squirrel The northern flying squirrel (''Glaucomys sabrinus'') is one of three species of the genus '' Glaucomys'', the only flying squirrels found in North America.Walker EP, Paradiso JL. 1975. ''Mammals of the World''. Baltimore: Johns Hopkins Universit ...
, but it is believed that in the past there were numerous vertebrate fungivores and that toxin development greatly lessened their number and forced these species to abandon fungi or diversify.


Mollusks

Many terrestrial
gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
mollusks Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is esti ...
are known to feed on fungi. It is the case in several
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
of
slugs Slug, or land slug, is a common name for any apparently shell-less terrestrial molluscs, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced ...
from distinct families. Among them are the
Philomycidae Philomycidae are a family of air-breathing land slugs (snails without shells or with only shell remnants). They are terrestrial pulmonate gastropod mollusks in the superfamily Arionoidea (according to the taxonomy of the Gastropoda by Bouc ...
(e. g. ''
Philomycus carolinianus ''Philomycus carolinianus'', common name the Carolina mantleslug, is a species of land slug, a terrestrial gastropod mollusk in the family Philomycidae. Anatomy These slugs create and use love dart A love dart (also known as a gypsobelu ...
'' and '' Phylomicus flexuolaris'') and ''
Ariolimacidae Ariolimacidae is a family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
'' ('' Ariolimax californianus''), which respectively feed on slime molds ( myxomycetes) and mushrooms (
basidiomycetes Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Bas ...
). Species of mushroom producing fungi used as food source by slugs include milk-caps, ''
Lactarius ''Lactarius'' is a genus of mushroom-producing, ectomycorrhizal fungi, containing several edible species. The species of the genus, commonly known as milk-caps, are characterized by the milky fluid ("latex") they exude when cut or damaged. Like ...
'' spp., the oyster mushroom, ''
Pleurotus ostreatus ''Pleurotus ostreatus'', the oyster mushroom, oyster fungus, or hiratake, is a common edible mushroom. It was first cultivated in Germany as a subsistence measure during World War I and is now grown commercially around the world for food. It is ...
'' and the penny bun, ''
Boletus edulis ''Boletus edulis'' (English: cep, penny bun, porcino or porcini) is a basidiomycete fungus, and the type species of the genus ''Boletus''. Widely distributed in the Northern Hemisphere across Europe, Asia, and North America, it does not occu ...
''. Other species pertaining to different genera, such as ''
Agaricus ''Agaricus'' is a genus of mushrooms containing both edible and poisonous species, with over 400 members worldwide and possibly again as many disputed or newly-discovered species. The genus includes the common ("button") mushroom ('' Agaricus bi ...
'', ''
Pleurocybella ''Pleurocybella'' is a genus of fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are ...
'' and ''
Russula ''Russula'' is a very large genus composed of around 750 worldwide species of ectomycorrhizal mushrooms. They are typically common, fairly large, and brightly colored – making them one of the most recognizable genera among mycologists and mushr ...
'', are also eaten by slugs. Slime molds used as food source by slugs include ''
Stemonitis axifera ''Stemonitis axifera'' is a species of slime mold. It fruits in clusters on dead wood, and has distinctive tall reddish-brown sporangia, supported on slender stalks. Taxonomy The species was first described as ''Trichia axifera'' by Jean Baptis ...
'' and ''
Symphytocarpus flaccidus ''Symphytocarpus'' is a genus of slime molds in the family Stemonitidaceae Stemonitidaceae is an family of slime molds in the order Stemonitidales. It was first circumscribed by Elias Magnus Fries in 1829. Genera *'' Leptoderma'' *'' Macbr ...
''. Some slugs are selective towards certain parts or developmental stages of the fungi they eat, though this behavior varies greatly. Depending on the species and other factors, slugs eat only fungi at specific stages of development. Moreover, in other cases, whole mushrooms can be eaten, without any trace of selectivity.


Insects

In 2008, '' Euprenolepis procera'' a species of ant from the rainforests of South East Asia was found to harvest mushrooms from the rainforest. Witte & Maschwitz found that their diet consisted almost entirely of mushrooms, representing a previously undiscovered feeding strategy in ants. Several
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
families, including the
Erotylidae ''Ischyrus quadripunctatus'' Erotylidae, or the pleasing fungus beetles, is a family of beetles belonging to Cucujoidea containing over 100 genera. In the present circumscription, it contains 6 tribes ( Tritomini, Dacnini, Megalodacnini, Er ...
,
Endomychidae Endomychidae, or handsome fungus beetles, is a family of beetles with representatives found in all biogeographic realms. There are around 120 genera and 1300 species. The family was established based on the type genus '' Endomychus'', a genus ere ...
, and certain
Tenebrionidae Darkling beetle is the common name for members of the beetle family Tenebrionidae. The number of species in the Tenebrionidae is estimated at more than 20,000 and the family is cosmopolitan in distribution. Taxonomy ''Tenebrio'' is the Latin gen ...
also are specialists on fungi, though they may eat other foods occasionally. Other insects, like fungus gnats and
scuttle flies The fly ''Megaselia scalaris'' is a member of the order Diptera and the family Phoridae, and it is widely distributed in warm regions of the world. The family members are commonly known as the "humpbacked fly", the "coffin fly", and the "scuttle ...
, utilize fungi at their larval stage. Feeding on fungi is crucial for dead wood eaters as this is the only way to acquire nutrients not available in nutritionally scarce dead wood.


Birds

Jays ('' Perisoreus'') are believed to be the first birds in which mycophagy was recorded. Canada jays ('' P. canadensis''), Siberian jays ('' P. infaustus'') and Oregon jays ('' P. obscurus'') have all been recorded to eat mushrooms, with the stomachs of Siberian jays containing mostly fungi in the early winter. The ascomycete, '' Phaeangium lefebvrei'' found in north Africa and the Middle East is eaten by migrating birds in winter and early spring, mainly be species of lark (
Alaudidae Larks are passerine birds of the family Alaudidae. Larks have a cosmopolitan distribution with the largest number of species occurring in Africa. Only a single species, the horned lark, occurs in North America, and only Horsfield's bush lark occ ...
).
Bedouin The Bedouin, Beduin, or Bedu (; , singular ) are nomadic Arabs, Arab tribes who have historically inhabited the desert regions in the Arabian Peninsula, North Africa, the Levant, and Mesopotamia. The Bedouin originated in the Syrian Desert ...
hunters have been reported to use ''P. lefebvrei'' as bait in traps to attract birds. The ground-foraging Superb Lyrebird ''Menura novaehollandiae'' has also been found to opportunistically forage on fungi. Fungi are known to form an important part of the diet of the southern cassowary (''
Casuarius casuarius The southern cassowary (''Casuarius casuarius''), also known as double-wattled cassowary, Australian cassowary or two-wattled cassowary, is a large flightless black bird. It is one of the three living species of cassowary, alongside the dwarf ...
'') of Australia.
Bracket fungi Polypores are a group of fungi that form large fruiting bodies with pores or tubes on the underside (see Delimitation for exceptions). They are a morphological group of basidiomycetes-like gilled mushrooms and hydnoid fungi, and not all polypo ...
have been found in their droppings throughout the year, and Simpson in the ''Australasian Mycological Newsletter'' suggested it is likely they also eat species of
Agaricales The fungal order Agaricales, also known as gilled mushrooms (for their distinctive gills) or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13,000 described species, alo ...
and
Pezizales The Pezizales are an order of the subphylum Pezizomycotina within the phylum Ascomycota. The order contains 16 families, 199 genera, and 1683 species. It contains a number of species of economic importance, such as morels, the black and white ...
but these have not been found in their droppings since they disintegrate when they are eaten. Emus (''
Dromaius novaehollandiae The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus ''Dromaius''. The emu ...
'') will eat immature ''
Lycoperdon ''Lycoperdon'' is a genus of puffball mushrooms. The genus has a widespread distribution and contains about 50 species. In general, it contains the smaller species such as the pear-shaped puffball and the gem-studded puffball. It was formerly cla ...
'' and ''
Bovista ''Bovista'' is a genus of fungi commonly known as the true puffballs. It was formerly classified within the now-obsolete order Lycoperdales, which, following a restructuring of fungal taxonomy brought about by molecular phylogeny, has been spl ...
'' fungi if presented to them as will brush turkeys ('' Alectura lathami'') if offered ''
Mycena ''Mycena'' is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or bro ...
'', suggesting that species of Megapodiidae may feed opportunistically on mushrooms.


Microbial


Fungi

Mycoparasitism occurs when any fungus feeds on other fungi, a form of
parasitism Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
, our knowledge of it in natural environments is very limited.Free version
/ref> ''
Collybia ''Collybia'' (in the strict sense) is a genus of mushrooms in the family Tricholomataceae. The genus has a widespread but rare distribution in northern temperate areas, and contains three species that grow on the decomposing remains of other mus ...
'' grow on dead mushrooms. The fungal genus, ''
Trichoderma ''Trichoderma'' is a genus of fungi in the family Hypocreaceae that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts. This ref ...
'' produces
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s such as
chitinase Chitinases (EC 3.2.1.14, chitodextrinase, 1,4-β-poly-N-acetylglucosaminidase, poly-β-glucosaminidase, β-1,4-poly-N-acetyl glucosamidinase, poly ,4-(N-acetyl-β-D-glucosaminide)glycanohydrolase, (1→4)-2-acetamido-2-deoxy-β-D-glucan glycano ...
s which degrade the
cell walls A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...
of other fungi.Free version
/ref> They are able to detect other fungi and grow towards them, they then bind to the hyphae of other fungi using
lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in rec ...
s on the host fungi as a receptor, forming an
appressorium An appressorium is a specialized cell typical of many fungal plant pathogens that is used to infect host plants. It is a flattened, hyphal "pressing" organ, from which a minute infection peg grows and enters the host, using turgor pressure capabl ...
. Once this is formed, ''Trichoderma'' inject toxic enzymes into the host and probably
peptaibol Peptaibols are biologically active peptides containing between seven and twenty amino acid residues, some of which are non-proteinogenic amino acids. In particular, they contain α-aminoisobutyric acid along with other unusual aminoacids such as ...
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...
s, which create holes in the cell wall, allowing ''Trichoderma'' to grow inside of the host and feed.free version
''Trichoderma'' are able to digest
sclerotia A sclerotium (; (), is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant until favor ...
, durable structures which contain food reserves, which is important if they are to control pathogenic fungi in the long term. ''Trichoderma'' species have been recorded as protecting crops from ''
Botrytis cinerea ''Botrytis cinerea'' is a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes. In viticulture, it is commonly known as "botrytis bunch rot"; in horticulture, it is usually called "grey mould" or ...
'', ''
Rhizoctonia solani ''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name '' ...
'', '' Alternaria solani'', '' Glomerella graminicola'', '' Phytophthora capsici'', ''
Magnaporthe grisea ''Magnaporthe grisea'', also known as rice blast fungus, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, Johnson spot, neck blast, wheat blast, and Imochi ( Japanese:稲熱) is ...
'' and ''
Colletotrichum lindemuthianum ''Colletotrichum lindemuthianum'' is a fungus which causes anthracnose, or black spot disease, of the common bean plant (''Phaseolus vulgaris''). It is considered a hemibiotrophic pathogen because it spends part of its infection cycle as a biotr ...
''; although this protection may not be entirely due to ''Trichoderma'' digesting these fungi, but by them improving
plant disease resistance Plant disease resistance protects plants from pathogens in two ways: by pre-formed structures and chemicals, and by infection-induced responses of the immune system. Relative to a susceptible plant, disease resistance is the reduction of pathoge ...
indirectly.


Bacteria

Bacterial mycophagy was a term coined in 2005, to describe the ability of some bacteria to "grow at the expense of living fungal hyphae". In a 2007 review in the ''
New Phytologist ''New Phytologist'' is a peer-reviewed scientific journal published on behalf of the New Phytologist Foundation by Wiley-Blackwell. It was founded in 1902 by botanist Arthur Tansley, who served as editor until 1931. Topics covered ''New Phytolo ...
'' this definition was adapted to only include bacteria which play an active role in gaining nutrition from fungi, excluding those that feed off passive secretions by fungi, or off dead or damaged hyphae. The majority of our knowledge in this area relates to interactions between bacteria and fungi in the soil and in or around plants, little is known about interactions in marine and freshwater habitats, or those occurring on or inside animals. It is not known what effects bacterial mycophagy has on the fungal
communities A community is a social unit (a group of living things) with commonality such as place, norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area (e.g. a country, village, to ...
in nature. There are three mechanisms by which bacteria feed on fungi; they either kill fungal cells, cause them to secrete more material out of their cells or enter into the cells to feed internally and they are categorised according to these habits. Those that kill fungal cells are called nectrotrophs, the molecular mechanisms of this feeding are thought to overlap considerably with bacteria that feed on fungi after they have died naturally. Necrotrophs may kill the fungi through digesting their cell wall or by producing toxins which kill fungi, such as tolaasin produced by '' Pseudomonas tolaasii''. Both of these mechanisms may be required since fungal cell walls are highly complex, so require many different enzymes to degrade them, and because experiments demonstrate that bacteria that produce toxins cannot always infect fungi. It is likely that these two systems act synergistically, with the toxins killing or inhibiting the fungi and
exoenzyme An exoenzyme, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside that cell. Exoenzymes are produced by both prokaryotic and eukaryotic cells and have been shown to be a crucial component of many biological ...
s degrading the cell wall and digesting the fungus. Examples of necrotrophs include ''
Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...
'' which feed on ''
Cryptococcus neoformans ''Cryptococcus neoformans'' is an encapsulated yeast belonging to the class Tremellomycetes and an obligate aerobe that can live in both plants and animals. Its teleomorph is a filamentous fungus, formerly referred to ''Filobasidiella neoformans ...
'', ''
Aeromonas ''Aeromonas'' is a genus of Gram-negative, facultative anaerobic, rod-shaped bacteria that morphologically resemble members of the family Enterobacteriaceae. Most of the 14 described species have been associated with human diseases. The most imp ...
caviae'' which feed on ''
Rhizoctonia solani ''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name '' ...
'', '' Sclerotium rolfsii'' and ''
Fusarium oxysporum ''Fusarium oxysporum'' (Schlecht as emended by Snyder and Hansen), an ascomycete fungus, comprises all the species, varieties and forms recognized by Wollenweber and Reinking within an infrageneric grouping called section Elegans. It is part of ...
'', and some
myxobacteria The myxobacteria ("slime bacteria") are a group of bacteria that predominantly live in the soil and feed on insoluble organic substances. The myxobacteria have very large genomes relative to other bacteria, e.g. 9–10 million nucleotides except ...
which feed on '' Cochliobolus miyabeanus'' and ''
Rhizoctonia solani ''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name '' ...
''. Bacteria which manipulate fungi to produce more secretions which they in turn feed off are called
extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...
biotrophs; many bacteria feed on fungal secretions, but do not interact directly with the fungi and these are called
saprotroph Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...
s, rather than biotrophs. Extracellular biotrophs could alter fungal
physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemic ...
in three ways; they alter their
development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...
, the permeability of their membranes (including the efflux of nutrients) and their
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ...
. The precise signalling molecules that are used to achieve these changes are unknown, but it has been suggested that
auxin Auxins (plural of auxin ) are a class of plant hormones (or plant-growth regulators) with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essenti ...
s (better known for their role as a
plant hormone Plant hormone (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pat ...
) and
quorum sensing In biology, quorum sensing or quorum signalling (QS) is the ability to detect and respond to cell population density by gene regulation. As one example, QS enables bacteria to restrict the expression of specific genes to the high cell densities at ...
molecules may be involved. Bacteria have been identified that manipulate fungi in these ways, for example mycorrhiza helper bacteria (MHBs) and ''
Pseudomonas putida ''Pseudomonas putida'' is a Gram-negative, rod-shaped, saprotrophic soil bacterium. Based on 16S rRNA analysis, ''P. putida'' was taxonomically confirmed to be a ''Pseudomonas'' species (''sensu stricto'') and placed, along with several other ...
'', but it remains to be demonstrated whether the changes they cause are directly beneficial to the bacteria. In the case of MHBs, which increase infection of plant roots by
mycorrhizal   A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the pl ...
fungi, they may benefit, because the fungi gain nutrition from the plant and in turn the fungi will secrete more sugars. The third group, that enter into living fungal cells are called endocellular biotrophs. Some of these are transmitted vertically whereas others are able to actively invade and subvert fungal cells. The molecular interactions involved in these interactions are mostly unknown. Many endocellular biotrophs, for example some ''
Burkholderia ''Burkholderia'' is a genus of Pseudomonadota whose pathogenic members include the ''Burkholderia cepacia'' complex, which attacks humans and ''Burkholderia mallei'', responsible for glanders, a disease that occurs mostly in horses and related ...
'' species, belong to the β-proteobacteria which also contains species which live inside the cells of
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
s and amoeba. Some of them, for example ''
Candidatus In prokaryote nomenclature, ''Candidatus'' (Latin for candidate of Roman office) is used to name prokaryotic phyla that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S sequencing or metagenomics, provide m ...
'' Glomeribacter gigasporarum, which colonises the spores of '' Gigaspora margarita'', have reduced
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
sizes indicating that they have become entirely dependent on the metabolic functions of the fungal cells in which they live. When all the endocellular bacteria inside ''G. margarita'' were removed, the fungus grew differently and was less fit, suggesting that some bacteria may also provide services to the fungi they live in.


Ciliates

The
ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a differen ...
family Grossglockneridae, including the species '' Grossglockneria acuta'', feed exclusively on fungi. ''G. acuta'' first attaches themselves to a hyphae or sporangium via a feeding tube and then a ring-shaped structure, around 2 μm in diameter is observed to appear on the fungus, possibly consisting of degraded cell wall material. ''G. acuta'' then feeds through the hole in the cell wall for, on average, 10 minutes, before detaching itself and moving away. The precise mechanism of feeding is not known, but it conceivably involves
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s including
acid phosphatase Acid phosphatase (EC 3.1.3.2, acid phosphomonoesterase', phosphomonoesterase, glycerophosphatase, acid monophosphatase, acid phosphohydrolase, acid phosphomonoester hydrolase, uteroferrin, acid nucleoside diphosphate phosphatase, orthophosphoric-m ...
s,
cellulase Cellulase (EC 3.2.1.4; systematic name 4-β-D-glucan 4-glucanohydrolase) is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccha ...
s and
chitinase Chitinases (EC 3.2.1.14, chitodextrinase, 1,4-β-poly-N-acetylglucosaminidase, poly-β-glucosaminidase, β-1,4-poly-N-acetyl glucosamidinase, poly ,4-(N-acetyl-β-D-glucosaminide)glycanohydrolase, (1→4)-2-acetamido-2-deoxy-β-D-glucan glycano ...
s.
Microtubule Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27  nm and have an inner diameter between 1 ...
s are visible in the feeding tube, as are possible reserves of
cell membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (t ...
, which may be used to form food
vacuole A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic m ...
s filled with the cytoplasm of the fungus, via
endocytosis Endocytosis is a cellular process in which substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material. ...
, which are then transported back into ''G. acuta''. The holes made by ''G. acuta'' bear some similarities to those made by amoeba, but unlike amoeba ''G. acuta'' never engulfs the fungus.


Plants

Around 90% of land plants live in
symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or para ...
with
mycorrhizal   A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the pl ...
fungi, where fungi gain sugars from plants and plants gain
nutrients A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excr ...
from the soil via the fungi. Some species of plant have evolved to manipulate this symbiosis, so that they no longer give fungi sugars that they produce and instead gain sugars from the fungi, a process called myco-heterotrophy. Some plants are only dependent on fungi as a source of sugars during the early stages of their
development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...
, these include most of the
orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of floweri ...
s as well as many
fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...
s and lycopods. Others are dependent on this food source for their entire lifetime, including some orchids and
Gentianaceae Gentianaceae is a family of flowering plants of 103 genera and about 1600 species. Etymology The family takes its name from the genus ''Gentiana'', named after the Illyrian king Gentius. Distribution Distribution is cosmopolitan. Characteristi ...
, and all species of
Monotropaceae Monotropoideae, sometimes referred to as monotropes, are a flowering plant subfamily in the family Ericaceae. Members of this subfamily are notable for their mycoheterotrophic and non-photosynthesizing or achlorophyllous characteristics. Descrip ...
and
Triuridaceae Triuridaceae are a family of tropical and subtropical flowering plants, including nine genera with a total of approximately 55 known species. All members lack chlorophyll and are mycoheterotrophic (obtain food by digesting intracellular fungi, o ...
. Those that are dependent on fungi, but still
photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ...
e are called
mixotroph A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a single trophic mode on the continuum from complete autotrophy at one end to heterotrophy at the other. It is estimated that mixotrophs comp ...
s since they gain nutrition in more than one way, by gaining a significant amount of sugars from fungi, they are able to grow in the deep shade of forests. Examples include the orchids ''
Epipactis ''Epipactis'', or helleborine, is a genus of terrestrial orchids consisting of approximately 70 species. This genus is abbreviated as Epcts in horticultural trade. Description Their creeping, fleshy rhizomes grow offshoots, from which then eme ...
'', ''
Cephalanthera ''Cephalanthera'', abbreviated Ceph in horticultural trade, is a genus of mostly terrestrial orchids. Members of this genus have rhizomes rather than tubers. About 15 species are currently recognized, most of them native to Europe and Asia. The ...
'' and '' Plantanthera'' and the tribe Pyroleae of the family
Ericaceae The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with c.4250 known species spread across 124 genera, making it th ...
. Others, such as ''
Monotropastrum humile ''Monotropastrum humile'' is a species of myco-heterotrophic plant of the family Ericaceae, distributed throughout East Asia, eastern Asia, from the Himalayas to the List of islands of Japan, Islands of Japan. It lacks chlorophyll and is therefo ...
'', no longer photosynthesise and are totally dependent on fungi for nutrients. Around 230 such species exist, and this trait is thought to have
evolved independently Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last co ...
on five occasions outside of the orchid family. Some individuals of the orchid species ''
Cephalanthera damasonium ''Cephalanthera damasonium'', the white helleborine, is a species of orchid. It is widespread across much of Europe, the Middle East and Asia. ''Cephalanthera damasonium'' is the type species of the genus ''Cephalanthera''. Description ''Cep ...
'' are mixotrophs, but others do not photosynthesise. Because the fungi that myco-heterotrophic plants gain sugars from in turn gain them from plants that do photosynthesise, they are considered indirect
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
s of other plants. The relationship between orchids and orchid mycorrhizae has been suggested to be somewhere between
predation Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
and parasitism. The precise mechanisms by which these plants gain sugars from fungi are not known and has not been demonstrated scientifically. Two pathways have been proposed; they may either degrade fungal biomass, particularly the fungal hyphae which penetrate plant cells in a similar manner to in
arbuscular mycorrhiza An arbuscular mycorrhiza (AM) (plural ''mycorrhizae'', a.k.a. ''endomycorrhiza'') is a type of mycorrhiza in which the symbiont fungus (''AM fungi'', or AMF) penetrates the cortical cells of the roots of a vascular plant forming arbuscules. ( ...
e, or absorb sugars from the fungi by disrupting their
cell membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (t ...
s, through
mass flow Mass flow, also known as mass transfer and bulk flow, is the movement of fluids down a pressure or temperature gradient,Moyes & Schulte (2008). Principles of Animal Physiology. Pearson Benjamin Cummings. San Francisco, California particularly in ...
. To prevent the sugars returning to the fungi, they must compartmentalise the sugars or convert them into forms which the fungi cannot use.


Fungal farming


Insects

Three insect lineages, the beetles, ants and termites, independently evolved the ability to farm fungi between 40 and 60 million years ago. In a similar way to the way that human societies became more complex after the development of plant-based agriculture, the same occurred in these insect lineages when they evolved this ability and these insects are now of major importance in ecosystems. The methods that insects use to farm fungi share fundamental similarities with human agriculture. Firstly, insects inoculate a particular habitat or substrate with fungi, much in the same as humans plant seeds in fields. Secondly, they cultivate the fungi by regulating the growing environment to try to improve the growth of the fungus, as well as protecting it from pests and diseases. Thirdly they harvest the fungus when it is mature and feed on it. Lastly they are dependent on the fungi they grow, in the same way that humans are dependent on crops.


Beetles

Ambrosia beetle Ambrosia beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae ( Coleoptera, Curculionidae), which live in nutritional symbiosis with ambrosia fungi. The beetles excavate tunnels in dead, stressed, and healthy trees in wh ...
s, for example ''
Austroplatypus incompertus ''Austroplatypus incompertus'' is a species of ambrosia beetle belonging to the true weevil family, native to Australia, with a verified distribution in New South Wales and Victoria. It forms colonies in the heartwood of ''Eucalyptus'' trees and ...
'', farm
ambrosia fungi Ambrosia fungi are fungal symbionts of ambrosia beetles including the polyphagous and Kuroshio shot hole borers. There are a few dozen species described ambrosia fungi, currently placed in polyphyletic genera '' Ambrosiella'', '' Rafaellea'' and ' ...
inside of trees and feed on them. The mycangia (organs which carry fungal spores) of ambrosia beetles contain various species of fungus, including species of '' Ambrosiomyces'', ''
Ambrosiella ''Ambrosiella'' is a genus of ambrosia fungi within the family Ceratocystidaceae. It was circumscription (taxonomy), circumscribed by mycologists Josef Adolph von Arx and Grégoire L. Hennebert in 1965 with ''Ambrosiella xylebori'' as the type spe ...
'', '' Ascoidea'', '' Ceratocystis'', '' Dipodascus'', ''
Diplodia ''Diplodia'' is a genus of anamorphic fungi in the family Botryosphaeriaceae. Species *'' Diplodia abiegna'' *'' Diplodia abrotani'' *'' Diplodia abutilonis'' *'' Diplodia acaciae'' *'' Diplodia acaciarum'' *'' Diplodia acanthophylli'' *'' Dipl ...
'', '' Endomycopsis'', '' Monacrosporium'' and '' Tuberculariella''. The ambrosia fungi are only found in the beetles and their galleries, suggesting that they and the beetles have an
obligate {{wiktionary, obligate As an adjective, obligate means "by necessity" (antonym ''facultative'') and is used mainly in biology in phrases such as: * Obligate aerobe, an organism that cannot survive without oxygen * Obligate anaerobe, an organism tha ...
symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or para ...
.


Termites

Around 330 species of
termite Termites are small insects that live in colonies and have distinct castes ( eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blat ...
s in twelve genera of the subfamily
Macrotermitinae The Macrotermitinae, the fungus-growing termites, constitute a subfamily of the family Termitidae that is only found within the Old World tropics. This subfamily consists of 14 genera and about 350 species and are distinguished by the fact that ...
cultivate a specialised fungus in the genus ''
Termitomyces ''Termitomyces'' is a genus of basidiomycete fungi belonging to the family Lyophyllaceae. There are 30-40 species in the genus, all of which are completely dependent on termites to survive. They are the food source for a subfamily of termites, th ...
''. The fungus is kept in a specialised part of the nest in fungus cones. Worker termites eat plant matter, producing faecal pellets which they continuously place on top of the cone. The fungus grows into this material and soon produces immature mushrooms, a rich source of protein, sugars and enzymes, which the worker termites eat. The nodules also contain indigestible asexual spores, meaning that the faecal pellets produced by the workers always contain spores of the fungus that colonise the plant material that they defaecate. The ''Termitomyces'' also fruits, forming mushrooms above ground, which mature at the same time that the first workers emerge from newly formed nests. The mushrooms produce spores that are wind dispersed, and through this method, new colonies acquire a fungal strain. In some species, the genetic variation of the fungus is very low, suggesting that spores of the fungus are transmitted vertically from nest to nest, rather than from wind dispersed spores.


Ants

Around 220 described species, and more undescribed species of ants in the
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to confl ...
Attini cultivate fungi. They are only found in the
New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...
and are thought to have evolved in the
Amazon Rainforest The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. ...
, where they are most diverse today. For these ants, farmed fungi are the only source of food on which their
larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. T ...
are raised on and are also an important food for adults.
Queen ant A queen ant (formally known as a gyne) is an adult, reproducing female ant in an ant colony; generally she will be the mother of all the other ants in that colony. Some female ants, such as the ''Cataglyphis'', do not need to mate to produce offs ...
s carry a small part of fungus in small pouches in their mouthparts when they leave the nest to mate, allowing them to establish a new fungus garden when they form a new nest. Different lineages cultivate fungi on different substrates, those that evolved earlier do so on a wide range of plant matter, whereas
leaf cutter ants Leafcutter ants, a non-generic name, are any of 47 species of leaf-chewing ants belonging to the two genera ''Atta'' and ''Acromyrmex''. These species of tropical, fungus-growing ants are all endemic to South and Central America, Mexico, and ...
are more selective, mainly using only fresh leaves and flowers. The fungi are members of the families Lepiotaceae and Pterulaceae. Other fungi in the genus ''
Escovopsis ''Escovopsis'' is a genus of seven formally acknowledged parasitic microfungus species that rely on other fungi to be their hosts. This genus formally circumscribed with a single identified species in 1990; in 2013 three other species were added ...
''
parasitise Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
the gardens and
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...
-producing bacteria also inhabit the gardens.


Humans


Gastropods

The marine
snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class ...
'' Littoraria irrorata'', which lives in the
salt marsh A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is domin ...
es of the southeast of the United States feeds on fungi that it encourages to grow. It creates and maintains wounds on the grass, '' Spartina alterniflora'' which are then infected by fungi, probably of the genera '' Phaeosphaeria'' and ''
Mycosphaerella ''Mycosphaerella'' is a genus of ascomycota. With more than 10,000 species, it is the largest genus of plant pathogen fungi. The following introduction about the fungal genus ''Mycosphaerella'' is copied (with permission) from the dissertation o ...
'', which are the preferred diet of the snail. They also deposit faeces on the wounds that they create, which encourage the growth of the fungi because they are rich in nitrogen and fungal
hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...
. Juvenile snails raised on uninfected leaves do not grow and are more likely to die, indicating the importance of the fungi in the diet of ''L. irrorata''.


References

{{feeding Animals by eating behaviors Ecology terminology