Monday, 30 May 2011

Season of mists and mellow fruitfulness: truffle-like fungi

Truffles are fungi whose mushrooms don't open to release their spores.  Once upon a time they were all thought to be related, but non-opening mushrooms seem to have evolved many times independently, and there are basidiomycete truffles and ascomycete truffles.  (Ascomycetes and Basidiomycetes are the two largest groups of fungi; they include most of the fungi that we're familiar with.)  Typically, truffles have underground mushrooms that are dependent for spore dispersal on animals that can smell them, dig them up, and eat them.  In Europe this relationship is co-opted by truffle-collectors; dogs and pigs are used to find wild truffles in the forests.  In Australia there are truffle-like fungi that are dispersed by marsupial mammals.  Such fungi are often brown or pale in colour; not surprisingly, because most mammals don't have colour vision and rely on their sense of smell.

So what happens in New Zealand, where there are no native land mammals apart from bats and the odd lost seal?  We have a range of truffle-like fungi of various sizes and colours.  At least one, Weraroa erythrocephala, is bright red.  Others are purple, orange, or white.  New Zealand botanist and mycologist the late Ross Beever suggested these might be eaten by birds, which then disperse the spores.

These ones (probably W. erythrocephala) are common in the Wellington Botanic Gardens at the moment, among leaf litter and mulch.  They look for all the world like small fruits of for example pigeonwood (Hedycarya arborea) or creeping Fuchsia (Fuchsia procumbens).  

Something's been gnawing on this one.  It'd be interesting to investigate their scent, and whether weta are attracted to white and purple mushrooms, because Duthie et al. (2006) showed that weta eat some small-seeded berries and disperse their seeds.


Beever,  R . E.  (1993). Dispersal of truffle-like fungi in  New Zealand, in  R . S. Hill  ( ed. ), Southern Temperate Ecosystems: Origin and Diversification  22. Hobart, Australia.

Duthie, C., Gibbs, G., Burns, K.C., 2006. Seed dispersal by weta. Science 311, 1575.

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