Press release: Hidden insect diversity in grass shoots threatened by mowing

No. 17 - 13.02.2026

Researchers identify 255 insect species in grasses neglected by grassland management

When it comes to biodiversity, researchers and the public tend to focus on large-scale patterns. This overlooks a hidden but precious diversity: small, inconspicuous wasps, midges, flies, beetles and other insects that live in plants. These tiny creatures are actually very common, as shown by a team of researchers at the University of Göttingen and the Hungarian HUN-REN Centre for Ecological Research. The researchers measured, dissected and searched for insects in over 23,000 shoots of grass. They found 255 species of insects in ten perennial grass species, which last year-round, but not a single one in five annual, short-lived grass species. The longer the shoots of the perennial grass species, the higher the diversity of insects found in them. Around a third of the insect species feed directly on the grass. The remaining species, mostly wasps, live parasitically on the insects that feed on plants. Almost two-thirds of insects specialize in grasses, half of them even in specific grass species. The conclusion is that areas in grassland should not be mown for several years: stable insect populations need undisturbed refuges with intact shoots of grass. The results were published in Basic and Applied Ecology.

The team studied ubiquitous grasses that occur in large populations in many regions. These included five annual species such as black-grass and wind-grass, and ten longer-lasting species such as cat grass and couch grass. In autumn and winter, the researchers collected all insects from the shoots and classified them according to their respective species. They raised the larvae in the laboratory so that they could be clearly identified. They then analysed the “food web” – the multiple food chains – between the grasses, the plant-eating insects and the parasitic wasps that are their predators.

This revealed the diversity of insects hidden in shoots of grass. Eighty-three of the species found are plant-eaters such as grass flies and gall midges. The remaining 172 species are their natural enemies: tiny parasitic wasps whose larvae develop on or inside a host and attack and ultimately often kill it. On average, each perennial grass species is home to 12 plant-eating insect species that are attacked by 30 species of parasitic wasps. According to the data, perennial grass species with longer shoots attract more insects. This is explained by the fact that they are more visible and productive host plants with a more diverse food supply. The difficulty in predicting when and where short-lived annual grasses will grow seems to be the reason why only a few insects have evolved to specialize in them.

Regular mowing threatens the diversity of these many highly specialized insects. “The hidden wealth of insect species in shoots of grass is unfortunately largely ignored by grassland management, even though most species depend on the undisturbed development of grasses,” says lead author Professor Teja Tscharntke at Göttingen University. This community depends on intact grass shoots overwintering in minimally disturbed habitats. Therefore, unmown long-term refuges are needed. “The management of grasslands should pay much more attention to the neglected community of specialized insects in grass shoots,” adds Tscharntke.

Original publication: Teja Tscharntke, Péter Batáry, Stefan Vidal. “The hidden multitrophic diversity of specialized grass-shoot insects – neglected by grassland management.” Basic and Applied Ecology (2026). DOI: 10.1016/j.baae.2026.01.004

Images are licensed with CC BY 4.0 licence: https://creativecommons.org/licenses/by/4.0/

Contact:

Professor Teja Tscharntke

University of Göttingen

Department of Agricultural Ecology and Functional Agrobiodiversity

Grisebachstraße 6, 37077 Göttingen, Germany

Tel: +49 (0)551 39-29205

Email: ttschar@gwdg.de