Australian Truffle-like fungi (earthballs)

Zelleromyces-cf-daucinus_cross_sect_14062020.jpg

Australian Truffle-like fungi

Also known as 'earthballs', because of their generally rounded shape and also due to Australian truffle-like fungi often form underground, or at the soil surface under leaf litter. 

 

Relatively little is known about truffle-like fungi in Australia, but around 50% of the truffle-like fungi genera found here are endemic (found nowhere else). Even more amazing is that when it comes to species, the level of endemism is about 95%" (ANBG 2012).

 

This could be attributed to Australia's relative isolation, climatic and habitats influencing the evolution of Australia's truffle-like fungi.

‘What diversity might be found on the mainland, if mycologists were but to look.’

 

(Tasmanian Botanist Leonard Rodway, commenting on the considerable number of new  truffle-like fungi species found in a relatively small area of Tasmania, 1912.)

Australian truffle-like fungi earthball Tasmania
DNA

While truffle-like fungi share features in common, they do not come from a common ancestor. DNA research shows fungi have evolved from "truffle-like" to "mushroom-like", and also the other direction, from "mushroom-like" to "truffle-like", resulting in families having members that are typical 'above ground mushroom like' species, and members that are 'truffle-like species'!

Fun Fact!

 

Evidence suggests that above-ground stinkhorns evolved from truffle-like fungi ancestors!

Stinkhorns evolved from truffle-like fungi ancestors.
Truffle-like fungi wet eucalypt habitat, Tasmania.

Look for Truffle-like fungi in leaf litter in wet eucalypt forest.

  • Far North Queensland is a truffle-like fungi hotspot in Australia! Species seem to be extremely diverse at the boundaries between eucalypt and rainforest in north Queensland

  • Seasonally abundant - truffle-like fungi appear to be more abundant with wetter months - winter in the southern half of Australia, and summer in the northern parts of Australia. eg: Mesophellia in summer with its dry, outer casing.

  • After fire - the fungal remains after mammals have dug them up .

Finding truffle-like fungi

Researchers suggest around there may be up 1200-2400 of truffle-like fungi species in Australia. Found across many habitats including deserts, tropical rainforests of Queensland, temperate rainforests of Tasmania, dry eucalypt forest in South Australia, wet eucalypt forest in Victoria, open woodlands of Western Australia.

 

The truffle-like fungi fruitbodies are typically small (a few mm - several cm) and roundish,  soft, spongy to hard, in a variety of colours including white, pink, orange, brown. Some researchers have found truffle-like fungi may be 1-2 metres from the base of Eucalyptus, Acacia,  Allocasuarina, Leptospermumand Nothofagus regardless of tree size.

Australian truffle-like fungi may favour slopes, gullies or ridges as well as occupy different levels in the soil structure depending on species. Mesophellia glauca prefers deep soil on slopes and ridges, where as Zelleromyces spp. are to be found in the upper leaf litter layer in wet gullies.  

Underground truffle-like fungi, Huon Valley, Tasmania.

After fires, native mammals detect and dig up the underground truffles as an important source of food.

Tasmanian Bettong
Arcangeliella sp. Earthball, underground truffle-like fungi, Huon Valley, Tasmania.
Big Tree

This plant <=> fungus <=> mammal relationship important for maintaining the biological and functional diversity of Australian landscapes.

Beneficial Relationships

Sequestrate truffle-like fungi, are a type of mycorrhizal fungi, that form beneficial relationships with trees. The hyphae of the fungi connect to the roots of trees (in Australia for example this may include Gum Trees (Eucalypts), forming mycorrhizal connections.  Receiving sugars from photosynthesis of the plant, in return, the fungus helps provides the plant with water, nutrients and protection against pathogens. 

Truffle-like fungi have lost the ability to forcibly discharge their spores, relying on mycophagous (fungi eating), fauna to dig up and disperse the fungal spores.

 

When the fruit bodies of the truffle-like fungi are mature, they produce irresistable odours that have been described as nutty, fruity, cheesy, spicy or foetid! The wildlife dig up and eat the truffle-like fungi they help deposit the spores through fecal pellets.

Rains wash the spores into the soil, worms and dung beetles deposit spores. Dung beetles have even been observed gathering at the anal opening of a Tasmanian Bettong, attaching themselves to the fecal pellet as it drops to the ground and then burying the dung in the ground!

Australian Fungi Loving Fauna

Rodents and Australian Rat Kangaroos love truffle-like fungi the most.

80-90% of the diet of the Australian Long-footed Potaroo (Potorus longipes) consists of underground truffle-like fungi regardless of season.

The Long-nosed Potoroo (Potorous tridactylus) may eat over 40 different species at a single site and fungi may form around 30-40% of their diet with the peak of feeding during the wetter seasons where it forages in gullies.

The Tasmanian Bettong (Bettongia gaimardi ) eats at least 49 species.

Rat Kangaroos have a foregut that allows them to be better able to digest the nutrients in the fungi compared to other mammals.

Bettongia gaimardi Tasmanian Bettong

(Freycinet, Gaimard, Quoy)

Australian native fauna recorded
as eating fungi

Over 30 species of native Australian fauna have been recorded as eating fungi. Not all of the ones listed eat truffle-like fungi, but have been included here out of interest.

Bennett's Wallaby - Macropus rufogriseus rufogriseus 

Bilby - Macrotis lagotis

Bush Rat - Rattus fuscipes

Common Brushtail Possum - Trichosurus vulpecula

Common Wombat - Vombatus ursinus 

Long-nosed Bandicoot - Perameles nasuta

Long-footed Potoroo - Potorous longipes 

Long-nosed Potoroo - Potorous tridactylus

Long-tailed Mouse - Pseudomys higginsi

Quokka - Setonix brachyurus

Red-legged Pademelon - Thylogale stigmatica

Southern Brown Bandicoot - Isoodon obesulus 

Swamp Rat - Rattus lutreolus

Swamp Wallaby - Wallabia bicolor

Tasmanian Bettong - Bettongia gaimardi 

Tasmanian Pademelon - Thylogale billardierii  

(Source: Claridge, Castellano & Trappe 1996)

References:

Australian National Botanical Gardens (ANBG) (2012). Truffle-like fungi in Australia, https://www.anbg.gov.au/fungi/truffle-like.html

 

A.W.Claridge, M.A. Castellano & J.M. Trappe, Fungi as a food resource for mammals in Australia, Fungi of Australia - Volume 1B:239-267 (1996).

Lebel, T. (1998). A revision of the sequestrate russulae of Australia and New Zealand.PhD. thesis. Oregon State University, Corvallis, Oregon.

Freycinet, L.C., Gaimard, P., Quoy, J.R.C., Ministere de I'interieur; France. (1817, 1818, 1819 et 1820) Voyage autour du monde : entrepris par ordre du roi... execute sur les corvettes de S. M. l'Uranie et la Physicienne, pendant les annees 1817, 1818, 1819 et 1820;

https://archive.org/details/VoyageAutourduM00Loui/page/n11/mode/2up

Further Readings on Australian underground truffle-like fungi.

A.W.Claridge, M.A. Castellano & J.M. Trappe, Fungi as a food resource for mammals in Australia, Fungi of Australia - Volume 1B:239-267 (1996).

Beaton, G., Peglar, D.N., & Young, T.W.K. (1984b). Gasteroid Basidomycota of Victoria State, Australia. II. Russulales. Kew Bulletin of Miscellaneous Information. 39. 669.698.

Danks, M.A., Simpson, N., Elliott, T.F., Paine, C.E.T. & Vernes, K. (2020). "Modeling mycorrhizal fungi dispersal by the mycophagous swamp wallaby (Wallabia bicolor)", Ecology and evolution, vol. 10, no. 23, pp. 12920-12928.

Elliott, T.F. & Vernes, K., 2021. Camera trap detection of mycophagy among co‐occurring vertebrates. Austral ecology, 46(3), pp.496–500.

Elliott, Todd F, Sally Townley, Charmaine Johnstone, Paul Meek, Ian Gynther, and Karl Vernes. "The Endangered Hastings River Mouse (Pseudomys Oralis) as a Disperser of Ectomycorrhizal Fungi in Eastern Australia." Mycologia 112.6 (2020): 1075-085. Web.

Lebel, T. (1998). A revision of the sequestrate russulae of Australia and New Zealand. PhD. thesis. Oregon State University, Corvallis, Oregon.

Lebel, T. (2002). Australasian sequestrate (truffle-like) fungi. XIII. Cystangium (Russulales, Basidiomycota), Australian Systematic Botany, vol.16, pp. 371-400.

Lebel, T. (2003). Australasian sequestrate (truffle-like) fungi. XIV. Gymnomyces (Russulales, Basidiomycota), Australian Systematic Botany, vol.16, pp. 401-426.

Sheedy, E.M., Ryberg, M., B, Lebel, May, T.W., Bougher, N.L., Matheny, P.B. (2016).

Dating the emergence of truffle-like fungi in Australia, by using an augmented meta-analysis, Australian Systematic Botany, 2016, vol.29, pp.284–302.http://dx.doi.org/10.1071/SB16025