Ah, petrichor! And beetles and bugs

Ever wonder if there’s a name for that particular smell that happens when it rains on hot dry dust? Well, there is – it’s petrichor.

According to the Oxford Dictionary, its origins are:

1960s: blend of petro- ‘relating to rocks’ (the smell is believed to be caused by a liquid mixture of organic compounds which collects in the ground) and ichor.

Wikipedia gives more:

The term was coined in 1964 by two Australian researchers, Bear and Thomas, for an article in the journal Nature.In the article, the authors describe how the smell derives from an oil exuded by certain plants during dry periods, whereupon it is absorbed by clay-based soils and rocks. During rain, the oil is released into the air along with another compound, geosmin, a metabolic by-product of certain Actinobacteria, which is emitted by wet soil, producing the distinctive scent; ozone may also be present if there is lightning. In a follow-up paper, Bear and Thomas (1965) showed that the oil retards seed germination and early plant growth. This would indicate that the plants exude the oil in order to safeguard the seeds from germination under duress.

We smelt it the other day, after a long time without rain. Lismore has had the driest summer in 115 years – the wet season just failed to materialise. Instead of the 100-300 mL we usually get in January and February, it’s been 55 and 34. It feels wrong, and I have to say that I’ve enjoyed a (relatively) less humid summer, but not the hot temperatures that sometimes came with it.

A charming visitor appeared last week. According to both the Australian Museum and the Queensland Museum, it’s a female Lyraphora obliquata. Not much is known about the habits or biology of this species.

Female Lyraphora obliquata, Larnook, Northern NSW

Female Lyraphora obliquata, Larnook, Northern NSW

The colourful bug below was photographed by a neighbour (the graininess is because it’s from an iPhone). It’s the nymph of the eucalyptus tip-wilter bug, Amorbus alternatus.

Nymph (youngster) of the eucalyptus tip-wilter bug, Amorbus alternatus

Nymph (youngster) of the eucalyptus tip-wilter bug, Amorbus alternatus

Brisbane Insects has photos of both the adult eucalyptus tip-wilter bugs and nymphs.

As you know, insects go through many stages before reaching the adult form, and these instars look nothing like the adult or, often, each other. All fun and games for the hapless insect identifier.

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5 Responses to Ah, petrichor! And beetles and bugs

  1. Roz says:

    Thanks for this one Joy. It’s good to know that new words are being coined and ‘petrichor’ has long been needed. And I love the beetles

    • Joy Window says:

      Thanks, Roz. It’s odd that this word has been around for 50 years, yet has not come into common usage. Yet everyone knows what you mean when you mention “that smell after rain”. I wonder if other languages have a word for it – they must have. By the way, I love your photography on your website, especially the ruins. I’m partial to ruins and old farm buildings myself.

      • Roz says:

        Hi Joy, thanks for your comments about my photos and site. More ruins and abandoned places are forthcoming – recently got my licence (62 year old red P plater) so now can get around independently. Similar interests and background but yours is far more academic and productive: proof reading but now mostly for friends, interest in bugs/beetles/nature etc but without the formal learning. I thoroughly enjoy your writings, thank you sharing with us.

        • Joy Window says:

          Hi Roz, thanks for your kind words. You are brave getting on the road, but will certainly find more ruins (and other stuff to photograph) that way. Take a road trip around Tassie if you can – lots of great ruins there, and interesting creatures of all kinds. I’ll keep an eye on your website. I don’t edit or proofread for friends – can cause offense! Maybe your author friends have tougher skins than mine đŸ™‚

  2. janebeau says:

    What a gorgeous new word – petrichor. I could hit the malls and demand a perfume with a top note of it! xx J

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