S. Mahunka szerk.: Folia Entomologica Hungarica 56. (Budapest, 1995)
'activity-trappability-abundance' these catches represent (Topping and Sunderland 1992, Sunderland etal. 1995). CONCLUSIONS One year of experience in using the hand-hold suction sampler for collecting mostly spiders demonstrated the usefulness and versatility of the method. The advantages include primarily that it is an absolute population estimating method that is relatively easy to use, provides a well preserved, clean material which, mostly in the case of live sorting, can be processed on the day of the sampling. A further advantage of the method is that it collects from a wider range of vegetational strata than do either sweep net sampling or pitfalls. However, this method is not the ultimate way of collecting all invertebrate animals. Although it collects from the ground surface, the wider taxonomic range of pitfall trap catches indicates that many groups are underrepresented in suction samples. The relatively small size of the collection area poses another problem which is a trade-off for light weight, portability and increased suction power as compared to the traditional backpack D-vac. Larger, fast moving animals, such as wolf spiders and carabid beetles might escape on the approach of the investigator, and thus become underrepresented in samples. Nevertheless, if limitations are kept in mind, it can be predicted that hand-hold suction samplers will provide in the future an increasing amount of useful information for entomologists. Acknowledgements - The authors are grateful to Mr J. Németh and Mrs Zs. Koncz for the technical assistance. This study was supported by the National Scientific Research Fund (OTKA grant No. F01 7691). F. Samu was supported by the Magyary Zoltán Scholarship scheme. REFERENCES Arnold, A. J. (1994): Insect suction sampling without nets, bags or filters. - Crop Protection 13: 73-76. De Barro, P. J. (1991): A cheap lightweight efficient vacuum sampler. - J. Aust. Entomol Soc. 30: 207-208. Dietrick, E. J. (1962): An improved backpack motor fan for suction sampling of insect populations. - J. Econ. Entomol. 54: 394-395. Füstös, L., Meszéna, Gy. and Simonne Mosolygó, N. (1986): A sokváltozós adatelemzés statisztikai módszerei. - Akadémiai Kiadó, Budapest, pp. 526. Győrffy, G. (1980): A "biocönométer" megépítésének egy lehetsége és gyakorlati alkalmazása. - Fol. ent. hung. 41: 366-369. Johnson, C. G., Southwood, T. R. E. and Entwistle, H. M. (1957): A new method of extracting arthropods and molluscs from grassland and herbage with a suction apparatus. - Bull. ent. Res. 48: 211-218.
