Nature on our doorsteps: Glowing in the dark

Rosaleen Dwyer is the County Heritage Officer at South Dublin County Council – every week she gives us an insight into nature on our doorsteps and the beautiful biodiversity of its plants and wildlife.

SOME creatures in nature have the ability to produce light.  This makes it appear as if they are glowing in the dark.

This ability is most often seen in certain mushrooms, marine fish and microscopic plankton, and some insects.

It is referred to as bioluminescence, where light is emitted by living things following a chemical reaction in their bodies.

It is thought that over 120 different mushroom species around the world can do this.

It can appear as a ghostly green light coming from either the mushroom’s overground fruiting body or from the threads of its root-like mycelium that live mostly underground.

The intensity of the light varies between fungal species, and it is not often visible to human eyes.

The tropical relatives of this native Irish Click Beetle can glow in the dark

Because, however, most of the light-emitting fungi live in dark woodlands, even a little bioluminescence may be enough to attract animals like squirrels, mice, slugs, and insects.

These creatures come to investigate the glowing mushroom, and as they walk over the fungus, they become covered in fungal spores.

In this way the creature helps to spread the spores to new locations in the wood where new fungal colonies will grow.

In Ireland, a common bioluminescent fungus is the Candle Snuff.

This small species grows in groups on decaying wood, especially the rotting stumps of broadleaved trees.

It grows no more than 6cm tall and it has elongated black stems and branches which grade to a grey colour, before finishing at the top with a white tip.

This makes it look like a snuffed-out candle wick, giving the fungus its name.

For this reason, it is also known as the Candlestick fungus.

While its name originated from how the fungus looks a bit like a candle, its name also ironically hints at this fungus’s natural ability to shed light, even if the light emitted is too faint for us humans to clearly see.