about this blog



I started this blog in 2008. It started mainly as a way of tracking the evolution of my dry garden, and that led to an interest in photography and in the creatures that live in the garden. It's still about the garden and wildlife, but now my passion is thinking about how we humans can learn to co-exist with wild animals and plants, especially in urban areas.

Tuesday, 9 April 2013

mystery tree


A few blocks away from my house, near a small group of shops, a tall, majestic gum tree grows.

















Its trunk is decorated by an attractive and intriguing wavy pattern. I'm wondering what caused the pattern in the bark?

Found along the eastern coast of Australia, are eucalypts  known as Scribbly Gums. They were first described by European botanists in the 1700s, and since then have fascinated generations of Australians and visitors.

Until recently the scientific understanding of the scribbles was blurry. In the 1930s, entomologists discovered that the larvae of a very small moth caused the scribbles, It was identified as a new species and named Ogmograptis scribula - the scribbly gum moth.

In 1999 an observant student compared the scribbles on different species of eucalypts, found they were different and suggested that more than one species of moth might be responsible.

In 2005 two species of moth were collected from a tree with two different scribble tracks. This provided proof that more than one species was involved, and helped scientists to learn about the life cycle of the moths.

But it wasn't until November 2012 that a breakthrough was made by a 'retired' moth expert, Dr Marianne Horak, working at the CSIRO National Insect Collection in an honorary capacity. Dr Horak discovered that there were at least 12 species of moths that made scribbles in bark, and described 11 new species of moth.

Scribbles appear on the trunks of about 20 species of eucalypt trees. They represent a unique plant-animal relationship. The scribbly gum moth larvae tunnel through the bark of the eucalypt in loops. In response to this the tree produces scar tissue cells that are very nutritious for the caterpillars, who turn around and eat their way back the way they came.  When mature, the caterpillar leaves the bark to spin a cocoon at the base of the tree. In time the bark drops off and the scribbles are visible.

There are lots of discoveries to be made in moth research.  Out of about 22 thousand species of moths only around half of these have been identified so far!

















I'm not sure if this tree is a scribbly gum. As I said, the pattern's more wave-like than scribbly. Maybe the moth responsible is one of the 11,000 not yet identified , and / or maybe it is a new Eucalypt species: Wavy Gum! 

Scribbly Gum Eucalyptus haemastoma
Scribbly Gum Moth - Australian Museum

29 comments:

  1. Fascinating how much of nature we are stll just beginning to learn about! The bark of the wavy gum is beautiful!

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    1. hi tog, it's tree art, isn't it?

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  2. I would call it a seismic gum as it looks like the waves made on one of those earthquake detecting machines...

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    1. now kirk, you can call it seismic gum if you wish, but I saw it first, so I claim official naming rights. At the moment I'm torn between calling it E. wavicus or E. catmintus.

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  3. that is so bizarre, it has to be true.

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    1. it's true - otherwise i would have published it on April 1st not 9th!

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  4. The bark is beautiful. We still have a lot to study and learn about nature..

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    1. we do, and we have to hurry because species sometimes go extinct before they are studied.

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  5. I never saw that wave pattern either. Interesting. I have seen insect damage in squiggles on bark though. Pesky buggers.

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    1. apparently it doesn't damage the tree.

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  6. You have to wonder if this benefits the tree in any way.

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    1. I don't know if there are specific benefits, but in one source it was described as a unique insect - plant interaction.

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  7. Fascinating! I've never seen that before. Tree bark is awesome, isn't it?!

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    1. being around mature trees is like being in an outdoor art gallery. I wish we humans could be proud of our ageing bark, seeing it as characterful.

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  8. Catmint, the wave-like pattern reminds of paintings by the great artist Van Gogh. It's beautiful ;-)

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    1. yes steph! I hadn't thought of it but I know what you mean.

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  9. Really interesting post Catmint, love the patterns created by the moth, very artistic! I'm glad to read though that they don't damage the trees as trees are so precious to us all.

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    1. thanks for visit and comment, Pauline.

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  10. So interesting! I agree that more research needs to be done on moths. Identifying butterflies is fairly easy, but rarely can I identify a moth. I love this little scribbly gum moth - what a fun thing to see on trees. Good that the scribbly gum moth is already named - nowadays they might be called graffiti moths! ;)

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  11. Wow that is so fascinating about the wavy patterns but I love the bark on both trees.

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    1. me too, but then I just love bark especially on mature gums.

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  12. Wow! To think that each type of moth has its own signature! I suspect scientists have only scratched the surface of what the squiggles mean and what the moths are conveying to each other!

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    1. it would also make a good sci fi or fantasy novel.

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  13. That's really interesting. I like Deb's idea that each scribble is a bit like a signature. I have fond memories of the eucalyptus trees in southern California, where I lived as a little kid. The scribbles make each tree unique. :o)

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  14. Like Tammy and Deb it is nice to think of the scribbles as a sort of signature. It is amazing that something quite small can have such a big impact on something quite large.

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  15. Hi Tammy and Jennifer, thanks for the visits and comments.

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  16. Amazing would be the best to describe it..

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