Chorthippus vagans sensitive to fungal attacks. At present Chorthippus vagans is in the Netherlands only represented in the area around Nijmegen. A population, which was visited around mid August 1996 after some humid days, proved to be heavily attacked by fungi. A few days later no alive specimen of this species could be recorded, while other Acrididae species present in the same habitat were still present. C. vagans is often referred to as a species of dry, sunny areas. This preference might be based on its incapability to cope with fungal attacks in more humid habitats. This might also explain why the species does not occur in other areas in the Netherlands.