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Effects of insecticide exposure on movement and population size estimates of predatory ground beetles (Coleoptera: Carabidae)
Pest Management Science
  • Jarrad R Prasifka, United States Department of Agriculture
  • Miriam D. Lopez, United States Department of Agriculture
  • Richard L Hellmich, United States Department of Agriculture
  • Patricia L. Prasifka, Iowa State University
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BACKGROUND: Estimates of arthropod population size may paradoxically increase following insecticide applications. Research with ground beetles (Coleoptera: Carabidae) suggests that such unusual results reflect increased arthropod movement and capture in traps rather than real changes in population size. However, it is unclear whether direct (hyperactivity) or indirect (prey-mediated) mechanisms produce increased movement.

RESULTS: Video tracking of Scarites quadriceps Chaudior indicated that brief exposure to lambda-cyhalothrin or tefluthrin increased total distance moved, maximum velocity and percentage of time moving. Repeated measurements on individual beetles indicated that movement decreased 240 min after initial lambda-cyhalothrin exposure, but increased again following a second exposure, suggesting hyperactivity could lead to increased trap captures in the field. Two field experiments in which ground beetles were collected after lambda-cyhalothrin or permethrin application attempted to detect increases in population size estimates as a result of hyperactivity. Field trials used mark–release–recapture methods in small plots and natural carabid populations in larger plots, but found no significant short-term (<6 day) increases in beetle trap captures.

CONCLUSION: The disagreement between laboratory and field results suggests mechanisms other than hyperactivity may better explain unusual changes in population size estimates. When traps are used as a primary sampling tool, unexpected population-level effects should be interpreted carefully or with additional data less influenced by arthropod activity


This article is from Pest Management Science; 64 (2008); 30-36; doi: 10.1002/ps.1460

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
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Jarrad R Prasifka, Miriam D. Lopez, Richard L Hellmich and Patricia L. Prasifka. "Effects of insecticide exposure on movement and population size estimates of predatory ground beetles (Coleoptera: Carabidae)" Pest Management Science Vol. 64 Iss. 1 (2008) p. 30 - 36
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