The efficiency of VortisTM 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 Vortis TM 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 Vortis TM . These differences may have contributed to the larger 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.

Suction samplers are typically used with touch-down samples, where the nozzle is held stationary on the ground, or within an open-ended cylinder, where the nozzle is moved through the enclosed vegetation. With touch-down sampling, published estimates suggest that virtually all individuals and species of grassland invertebrate are captured within 3 s. Effects of suction duration on catch when sampling within a cylinder have rarely been investigated. Here, it was found that extrapolation from studies of touch-down sampling, based on the relative areas of the G-vac nozzle and the cylinder, can be used to guide minimum sampling durations for Auchenorrhyncha (leafhoppers and planthoppers) when using a G-vac. Additional time, however, may be necessary when sampling Araneae (spiders), probably because movement of the G-vac nozzle within the cylinder results in disturbance of the vegetation such that more specimens are made available to be captured than with touch-down sampling.