Suction samplers for grassland invertebrates: comparison of numbers caught using Vortis™ and G-vac devices

1. The efficiency of Vortis TM and a modified garden leaf-blower/vacuum ‘G-vac’ sampler were compared by sampling invertebrates using standardised sample areas and suction times at three grassland sites. The G-vac caught more individuals of Araneae, Auchenorrhyncha, Thysanoptera and Hymenoptera than the Vortis. Numbers of Diptera did not differ between devices, but the VortisTM captured greater numbers of Coleoptera. 2. Estimated air velocity within the collecting nozzle was greater for the G-vac and its mode of application resulted in greater disturbance of the grass sward than with the VortisTM. These differences may have contributed to the lar- ger captures of certain taxa by the G-vac. 3. It is concluded that G-vacs can be applied with confidence as a credible alternative to the bespoke Vortis TM, and particularly for taxa which are most frequently sampled using suction samplers.