fungi that feed on nematodes (as the most abundant and convenient prey species) mostly live in nitrogen-deficient habitats. these fungi can be divided into four main groups according to the methods they use to catch their prey. some use a mechanical means, an adhesive or a mechanical hyphal trap. some produce a toxin and use it to immobilise the nematode. some are parasitic, using their spores to gain entry into their prey, and some are egg parasites, inserting their hyphal tips into the eggs or cysts, or into females before the eggs are deposited.