A fungus builds sticky nets when it detects nematodes

A predator at microscopic scale

A hypha can serve both as a growing filament and as part of a trap. Arthrobotrys flagrans develops adhesive networks that immobilise passing nematodes. Once an animal is captured, its body becomes a source of nutrients for the fungus. This is more than a fungus colonising an already dead animal: catching living prey forms part of its feeding strategy. A microscope reveals a relationship that a photograph of an ordinary mushroom cannot show.

Xiaodi Hu, Reinhard Fischer and colleagues investigated how the presence of an animal changes fungal cell activity. Their 2024 study identified a role for the receptor GprC in responding to nematode-associated signals. Removing the corresponding gene greatly reduced trap production. Restoring its function helped the researchers test whether that particular genetic change explained the effect.

Detection also changes the cell's energy supply

GprC works with the protein GasA. The authors connected this system both to signalling at the cell membrane and to mitochondrial activity. Building a trapping network therefore involves more than receiving information about potential food: the cell must also adjust its metabolism. Saying that the fungus “detects prey” describes a biochemical response. It does not imply conscious decisions or a nervous system.

A separate experiment with Arthrobotrys oligospora examined how volatile compounds lure nematodes towards a fungus. These examples should remain distinct. Attracting an animal and initiating a trap are different stages, and a result established in one fungal species cannot simply be assigned to another.

What the experiments can establish

The research uses particular strains, growth media and the model nematode Caenorhabditis elegans. It identifies mechanisms that can be challenged in further experiments. It does not measure the performance of a finished agricultural treatment, nor demonstrate control of every animal parasite. Moisture, alternative food and other soil organisms can change how the interaction unfolds outside the laboratory.

For someone exploring a forest, the useful shift is in what counts as fungal ecology. Fungi do more than decompose timber or exchange resources with roots. Predator–prey relationships also occur within a handful of soil. Documenting them requires microscopy, culture and experimental evidence; finding a nematode beside a filament is not by itself proof that a hunt is taking place.