Native grasshoppers munch on invasive weeds

Embargoed until: Publicly released: 2026-05-08 09:58

New Zealand

Photo by William Harland via iNaturalist (CC-BY)

The flightless and silent grasshoppers of the Southern Alps could be keeping mountain weeds under control. Researchers found despite the name "grasshopper", the insects avoid eating tough native tussock grass, instead going for the flowers, fruit and leaves of soft weeds that have invaded the area over the past 50 years. The researchers say the bugs could help ensure New Zealand mountains continue to be covered in native snow tussock, however the grasshoppers are at risk of losing their habitat due to climate change.

News release

From: Steve Trewick, Massey University (study author)

"Using a combination of plant cuticles and modern genetic techniques we explored dietary preferences among three species of endemic grasshopper that have overlapping ranges in the Southern Alps of Canterbury over a 50 year period.

"One of the findings was that the native grasshoppers are now including invasive weeds (e.g. mouse-ear Pilosella ) in their diets, which probably reflects the important influence of grasshoppers on plant composition in the alpine zone.

"We also found that despite the name “grasshopper” the species of Sigaus reject the abundant snow tussock grasses, instead preferring to eat leaves, flowers and fruits of herbs and small shrubs."

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Other Massey University, Web page Blog post: Grasshoppers that don’t like grass are helping our tussock grasslands

Research Wiley, Web page

Journal/
conference: Ecology and Evolution

Research:Paper

Organisation/s: Massey University, University of Canterbury

Funder: The work was supported by funding from the Miss E. L. Hellaby Indigenous Grassland Research Trust, The Orthopterists' Society and Entomological Society of New Zealand. Richard Watson was supported by a study grant from the New Zealand Forest Service aided by J.T Holloway, C.L. Batchler, G. Baker and Prof. R.A. Harrison.

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