Eur. J. Entomol. 112 (3): 520-524, 2015 | DOI: 10.14411/eje.2015.058

Suction sampling of grassland invertebrates using the G-vac: Quantifying and avoiding peripheral suction effects

Andrew CHERRILL
Entomology Research Group, Crop and Environment Sciences, Harper Adams University, Edgmond, Shropshire TF10 8NB, UK; e-mail: acherrill@harper-adams.ac.uk

Abstract. Suction sampling with modified garden leaf-blowers (G-vacs) is a widely used method for research on invertebrates in agricultural and grassland habitats. Approaches vary from sweeping the collecting nozzle across the surface of the vegetation within a known area, applying the nozzle firmly to the ground to delimit a sample area equal to nozzle crosssection, or applying the nozzle repeatedly within a larger open-ended cylinder placed on the ground. These approaches vary in potential for the inadvertent capture of specimens from outside of the sample area as a result of air being drawn into the nozzle from adjacent vegetation. This has never been studied adequately and is defined here for the first time as the Peripheral Suction Effect (PSE). Invertebrate species are likely to differ in susceptibility to PSE and so both sample size and composition could be impacted. This study compares two series of samples of Auchenorrhyncha taken using the same G-vac suction sampler (nozzle area, 0.01 m2) from areas enclosed and unenclosed by an open-ended cylindrical enclosure (area 0.17 m2) intended to prevent PSE. The unenclosed samples contained greater numbers of leafhoppers including Arthaldeus pascuellus, Javesella pellucida and immature Deltocephalinae. Numbers of immature Delphacinae did not differ between enclosed and unenclosed samples. The species composition of the two series of samples was similar, but the proportional representation of immature Delphacinae in unenclosed samples was diluted by the inflated numbers of other taxa that were drawn from the surrounding area. Peripheral suction effects are taxa-specific and therefore have the potential to bias measures of invertebrate community composition. Use of an open-ended cylinder to delimit the sample area is recommended as a simple, inexpensive and effective method of avoiding problems associated with PSE when using a G-vac. The potential for PSE with other models of suction samplers is discussed and questions for further research are identified.

Keywords: Hemiptera, Auchenorrhyncha, vacuum sampling, peripheral suction effect, D-vac, G-vac, Vortis

Received: September 8, 2014; Accepted: April 7, 2015; Prepublished online: May 15, 2015; Published: July 15, 2015

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References

  1. Barham D.F. & Stewart A.J.A. 2005: Differential indirect effects of excluding livestock and rabbits from chalk heath on the associated leafhopper (Hemiptera: Auchenorrhyncha) fauna. - J. Insect Conserv. 9: 351-361. Go to original source...
  2. Bell J.R., Wheater C.P., Henderson R. & Cullen R. 2002: Testing the efficiency of suction samplers (G-vacs) on spiders: the effect of increasing nozzle size and suction time. In Toft S. & Scharff N. (eds): European Arachnology 2000. Aarhus University Press, Aarhus, pp. 285-290.
  3. Biedermann R. & Niedringhaus R. 2009: The Plant- and LeafHoppers of Germany - Identification Key to All Species. Wissenschaftlich Akademischer Buchvertrieb-Fründ, Scheeßel, 409 pp.
  4. Borges P.A.V. & Brown V.K. 2003: Estimating species richness of arthropods in Azorean pastures: the adequacy of suction sampling and pitfall trapping. - Graellsia 59: 7-24. Go to original source...
  5. Brook A.J., Woodcock B.A., Sinka M. & Vanbergen A.J. 2008: Experimental verification of suction sampler capture efficiency in grasslands of differing vegetation height. - J. Appl. Ecol. 45: 1357-1363. Go to original source...
  6. Cherrill A.J. & Rushton S.P. 1993: The Auchenorrhyncha of an unimproved moorland in northern England. - Ecol. Entomol. 18: 95-103. Go to original source...
  7. Cherrill A.J. & Sanderson R.A. 1994: Comparison of sweep-net and pitfall trap sampling of moorland Hemiptera: evidence for vertical stratification within vegetation. - The Entomologist 113: 70-81.
  8. Doxon E.D., Davis C.A. & Fuhlendorf S.D. 2011: Comparison of two methods for sampling invertebrates: vacuum and sweep-netting. - J. Field Ornithol. 82: 60-67. Go to original source...
  9. Duffey E. 1974: Comparative sampling methods for grassland spiders. - Bull. Brit. Arachnol. Soc. 3: 34-37.
  10. Elliot N.C., Tao F.L., Fuentes-Granados R., Giles K.L., Elliot D.T., Greenstone M.H., Shufran K.A. & Royer T.A. 2006: D-vac sampling for predatory arthropods in winter wheat. - Biol. Contr. 38: 325-330. Go to original source...
  11. Henderson I.F. & Whitaker T.M. 1977: The efficiency of an insect suction sampler in grassland. - Ecol. Entomol. 2: 57-60. Go to original source...
  12. Hines J., Lynch M.E. & Denno R.F. 2005: Sap-feeding insect communities as indicators of habitat fragmentation and nutrient subsidies. - J. Insect Conserv. 9: 261-280. Go to original source...
  13. Hollier J.A., Maczey N., Masters G. & Mortimer S.R. 2005: Grassland leafhoppers (Hemiptera: Auchenorrhyncha) as indicators of habitat condition - a comparison of between-site and between-year differences in assemblage composition. - J. Insect Conserv. 9: 299-307. Go to original source...
  14. Hossain Z., Gurr G.M. & Wratten S.D. 1999: Capture efficiency of insect natural enemies from tall and short vegetation using vacuum sampling. - Ann. Appl. Biol. 135: 463-467. Go to original source...
  15. Littlewood N.A., Dennis P., Pakeman R.J. & Woodin S.J. 2006: Moorland restoration aids the reassembly of associated phytophagous insects. - Biol. Conserv. 132: 395-404. Go to original source...
  16. Littlewood N.A., Pakeman R.J. & Woodin S.J. 2009: Isolation of habitat patches limits colonisation by moorland Hemiptera. - J. Insect Conserv. 13: 29-36. Go to original source...
  17. Macleod A., Wratten S.D. & Harwood R.W.J. 1994: The efficiency of a new lightweight suction sampler for samplingaphids and their predators in arable land. - Ann. Appl. Biol. 124: 11-17. Go to original source...
  18. Maczey N., Masters G., Hollier J.A. & Mortimer S.R. 2005: Community associations of chalk grassland leafhoppers (Hemiptera: Auchenorryncha): conclusions for habitat conservation. - J. Insect Conserv. 9: 281-297. Go to original source...
  19. Morris M.G., Clarke R.T. & Rispin W.E. 2005: The success of a rotational grazing system in conserving the diversity of chalk grassland Auchenorrhyncha. - J. Insect Conserv. 9: 363-374. Go to original source...
  20. Nickel H. & Hildebrandt J. 2003: Auchenorrhyncha communities as indicators of disturbance in grasslands (Insecta, Hemiptera) - a case study from the Elbe flood plains (northern Germany). - Agr. Ecosyst. Environ. 98: 183-199. Go to original source...
  21. Rodwell J.S. 1992: British Plant Communities. Vol. 2. Grasslands and Montane Communities. Cambridge University Press, Cambridge, 552 pp.
  22. Samu F., Nemeth J. & Kiss B. 1997: Assessment of the efficiency of a hand-held suction device for sampling spiders: improved density estimation or oversampling? - Ann. Appl. Biol. 130: 371-378. Go to original source...
  23. Samu F. & Sarospataki M. 1995: Design and use of a hand-held suction sampler, and its comparison with sweep net and pitfall trap sampling. - Folia Entomol. Hungar. 56: 195-203.
  24. Sanders D. & Entling M.H. 2011: Large variation of suction sampling efficiency depending on arthropod groups, species traits and habitat properties. - Entomol. Exp. Appl. 138: 234-243. Go to original source...
  25. Standen V. 2000: The adequacy of collecting techniques for estimating species richness of grassland invertebrates. - J. Appl. Ecol. 37: 884-893. Go to original source...
  26. Stewart A.J.A. & Wright A.F. 1995: A new inexpensive suction apparatus for sampling arthropods in grasslands. - Ecol. Entomol. 20: 98-102. Go to original source...
  27. Stewart A.J.A. 2002: Techniques for sampling Auchenorrhyncha in grasslands. - Denisia 4: 491-512.
  28. Tormala T. 1982: Evaluation of five methods of sampling field layer arthropods, particularly the leafhopper community, in grassland. - Ann. Entomol. Fenn. 48: 1-16.