Jamie Morton is the NZ Herald's science reporter.

The sex life of one of NZ's strangest creatures

The head of a male New Zealand giraffe weevil can be up to half the length of its body. Photo/Supplied
The head of a male New Zealand giraffe weevil can be up to half the length of its body. Photo/Supplied

The secret sex life of one of New Zealand's strangest native species is going under the microscope in a new summer-long study.

University of Auckland student Madeleine Thom is exploring the post-mating behaviour of the New Zealand giraffe weevil, an odd-looking creature that can grow up to 9cm long, making it the country's longest beetle.

The 19-year-old's study is set to offer fresh insights into what remains a relatively little-understood species, once thought to be rare but now known to be commonly found in bush over most of the country.

The beetle can be found in logs on forest floors or on tree trunks, munching the dead wood of native trees with mouth parts at the end of a distinctive elongated snout that inspired its name.

As female weevils mate with multiple partners, this makes them an ideal species to study sperm competition and particularly how they balance the males' sperm and physical attributes as attractive traits.

Those males with longer snouts, or rostrums, tend to be stronger and therefore a better mate.

But Thom said smaller males also managed to mate, giving females a choice of whose sperm they used.

The study would focus on 50 females and 50 males gathered from West Auckland's Matuku Reserve and taken to mesh enclosures at a university lab.

Thom has moved them to her own backyard in Albany so she can continue her work during the summer.

"I'll be going away for a few days so I'm lucky my mum has agreed to look after them."

Her research supervisor, behavioural ecologist Dr Chrissie Painting, said the research could boost what we know about the quirky beetles.

University of Auckland student Madeleine Thom is exploring the post-mating behaviour of the New Zealand giraffe weevil - an odd-looking creature that can grow up to 9cm long, making it the country's longest beetle. Photo / Supplied
University of Auckland student Madeleine Thom is exploring the post-mating behaviour of the New Zealand giraffe weevil - an odd-looking creature that can grow up to 9cm long, making it the country's longest beetle. Photo / Supplied

"This project has the potential to reveal novel insights into mechanisms of post-copulatory sexual selection, and contribute to our understanding of the factors that drive relationships among pre- and post-copulatory sexual traits in nature."

Thom's study is part of a summer scholarship programme offered by the university to high achieving students.

- NZ Herald

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