Disc Mower Modifications to Reduce Suction Effects Do Not Decrease Insect Losses During Grassland Mowing

Among other anthropogenic factors, intensive agriculture, including frequent mowing, has largely contributed to the decline of the grassland fauna in Central Europe. Disc mowers, the predominant mowing technology, have long been suspected to cause high arthropod mortality mainly through suction generated by slanted blades. We compared a standard disc mower with two modified configurations designed to reduce suction, one equipped with a rear extension and the other fitted with straight (non‐slanted) blades and assessed their direct effects on arthropod abundance in agricultural grassland over two consecutive years. Mowing significantly reduced arthropod numbers compared to unmown controls, with no significant difference between standard and modified mowers. Only in Araneae, we found higher numbers when straight blades were used. This suggests that reducing the suction does not necessarily lead to lower insect mortality.