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Radar and opto-electronic measurements of the effectiveness of Rothamsted Insect Survey suction traps

Published online by Cambridge University Press:  10 July 2009

G. W. Schaefer
Affiliation:
Ecological Physics Research Group, Cranfield Institute of Technology, Cranfield, Bedford, MK43 OAL, UK
G. A. Bent
Affiliation:
Ecological Physics Research Group, Cranfield Institute of Technology, Cranfield, Bedford, MK43 OAL, UK
K. Allsopp
Affiliation:
Ecological Physics Research Group, Cranfield Institute of Technology, Cranfield, Bedford, MK43 OAL, UK

Abstract

Radar methods have been extended to measure the aerial density of small insects. Results obtained during an outbreak of the cereal aphid Metopolophium dirhodum (Walker) in south-eastern England were compared with simultaneous suction trap catches to study the sensitivity of trap effectiveness to windspeed. Two traps were studied: the Rothamsted Insect Survey trap (12·2-m) and a standard aerofoil trap. The Survey trap effectiveness is moderately sensitive to windspeed, decreasing exponentially by a factor of two for each 2·4 m/s (5 knots) of average windspeed. The two trap sensitivities did not differ significantly, but both results are very significantly different (P>0·001) from the published predictions, which were based upon a comparison of catches from suction traps and a combination of a rotary (whirligig) net and a tow net. These differences are discussed. The average catching rate is about 40% of that of an ideal trap. Seven-day catches could vary by a factor of 0·5—2·0 from average due to prolonged periods of extra strong or light winds. Systematic windspeed gradients can corrupt suction trap studies of insect dispersal in relation to vertical density profiles, diurnal flight patterns and geographical distribution. Absolute calibration of the aerofoil trap was achieved by using the remote-sensing IRADIT infra-red system to measure the aerial density of aphid-size insects near to the trap inlet in very light winds; the effectiveness was not statistically different from unity, and the Survey trap is expected to perform similarly.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1985

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References

Dewar, A. M., Woiwod, I. & Choppin De Janvry, E. (1980). Aerial migrations of the rose-grain aphid, Metopolophium dirhodum (Wlk.), over Europe in 1979.Pl. Path. 29, 101–109.CrossRefGoogle Scholar
Greenbank, D. O., Schaefer, G. W. & Rainey, R. C. (1980). Spruce budworm moth (Lepidoptera: Tortricidae) flight and dispersal: new understanding from canopy observations, radar, and aircraft.—Mem. entomol. Soc. Can, no. 110, 49 pp.Google Scholar
Schaefer, G. W. (1976). Radar observations of insect flight—pp. 157–197 in Rainey, R. C. (Ed.). Insect flight.—287 pp. Oxford, Blackwell Scientific (Symp. R. ent. Soc. Lond. no. 7).Google Scholar
Schaefer, G. W. (1979). An airborne radar technique for the investigation and control of migrating pest insects.—pp. 459465in Gunn, D. L. & Rainey, R. C. (Eds.). Strategy and tactics of control of migrant pests—Phil. Trans. R. Soc. (B) 287, 459465.Google Scholar
Schaefer, G. W. & Allsopp, K. (in press). Radar measurements of aphid migration and the interpretation of suction trap catches.Google Scholar
Schaefer, G. W., Bent, G. & Cannon, R. (1979). The green invasion.New Scient. 83, 440441.Google Scholar
Schaefer, G. W. & Bent, G. A. (1984). An infra-red remote sensing system for the active detection and automatic determination of insect flight trajectories (IRADIT).Bull. ent. Res. 74, 261278.CrossRefGoogle Scholar
Taylor, L. R. (1962). The absolute efficiency of insect suction traps.Ann. appl. Biol. 50, 405421.CrossRefGoogle Scholar
Taylor, L. R. (1979). The Rothamsted Insect Survey–an approach to the theory and practice of synoptic pest forecasting in agriculture—pp. 148185in Rabb, R. L. & Kennedy, G. G. (Eds.). Movement of highly mobile insects: concepts and methodology in research.—456 pp. Raleigh, N. Carolina St. Univ.Google Scholar
Taylor, L. R. & Palmer, J. M. P. (1972). Aerial sampling—pp. 189234in Van Emden, H. F. (Ed.). Aphid technology with special reference to the study of aphids in the field.—344 pp. London, Academic Press.Google Scholar
Taylor, L. R., French, R. A., Woiwod, I. P., Dupuch, M. J. & Nicklen, J. (1981). Synoptic monitoring for migrant insect pests in Great Britain and western Europe. I. Establishing expected values for species content, population stability and phenology of aphids and moths.Rep. Rorhamsted exp. Stn 1980 (2), 41104.Google Scholar
Woiwod, I. P., Tatchell, G. M. & Barrett, A. M. (1984). A system for the rapid collection, analysis and dissemination of aphid-monitoring data from suction traps.Crop Protection 3, 273288.CrossRefGoogle Scholar