13 Jul 2022

Our Changing World - Looking for stag beetles

From Afternoons, 3:35 pm on 13 July 2022

This is a(nother) tale of a native New Zealand underdog, and the passionate people who study them. No flashy feathers, no YouTube livestream, no pretending to be something its not for the limelight. And yes, it too is battling predators and habitat loss.

Luna is in the bush, wearing glasses, holding up her right hand which has a beetle on one of her fingers.

Luna Thomas holds up a stag beetle. Photo: Luna Thomas

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Meet the Helm’s stag beetle, Geodorcus helmsi, so named because of their enlarged mouthparts, or mandibles, that look like stag antlers. In general, they are pretty chill, moving slowly through life. The spend their days in the soil and at night they find a favourite tree to climb up to sip some sap.

It’s one of ten native stag beetles in the Geodorcus genus. It is also the most widespread – it has been found along the west and south coasts of the South Island – from Karamea in the north to Tapanui in the south and also on Rakiura Stewart Island.

Which is one of the field work sites for PhD student Luna Thomas’ research. She wants to get a better understanding of the behaviour and size and gender distribution of these beetles. To do that, she has to go beetle hunting, at night.

A hand holds a beetle with two red dots on it while a calipers measures the size of its head.

Taking beetle size measurements. Photo: Luna Thomas

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