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Ovipositional Response, Developmental Effects and Toxicity of Hexavalent Chromium to Megaselia scalaris, a Terrestrial Detritivore

  • John T. Trumble
  • Peter D. Jensen
Article

Abstract

The effects of hexavalent chromium (Cr VI) on ovipositional response, development, and survival of a common terrestrial detritivore, Megaselia scalaris (Diptera: Phoridae), were assessed in the laboratory. Ovipositing females did not discriminate between substrates containing 0, 50, 500, or 1000 µg/g, indicating a lack of avoidance behavior. Eggs placed on artificial diets containing up to 1000 µg/g either did not absorb Cr VI or were unaffected as measured by eclosion rates. However, development and survival of larvae were significantly reduced at the higher concentrations tested. Concentrations of 500 µg/g in their food increased larval development times by nearly 65%. At 1000 µg/g, larval developmental times doubled. The time required from onset to completion of pupariation was not significantly different regardless of Cr VI concentration. Although males eclosed before females, there was no significant difference between the sexes in the time required for adult eclosion. In addition, there were no signifi- cant differences in the percentage of males and females emerging from any of the treatments. At concentrations of 500 or 1000 µg/g, Cr VI decreased larval survival. Survival was reduced by 44.3% at 500 µg/g as compared with the controls. There was no additional mortality from the onset of the puparial stage to adult eclosion for larvae fed diets containing 500 µg/g Cr VI. At 1000 µg/g Cr VI, larval survival decreased by 86.6%. An additional 7.4% mortality was recorded in the puparial stage, for a decrease in total survival (larval plus puparial stages) of 94%. Thus, nearly all of the observed mortality occurred during the larval stage rather than the puparial stage. The population level implications of lack of avoidance of contaminated food and the effects of increased developmental times and reduced survivorship are discussed.

Keywords

Avoidance Behavior Developmental Time Artificial Diet Hexavalent Chromium Larval Survival 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 2004

Authors and Affiliations

  • John T. Trumble
    • 1
  • Peter D. Jensen
    • 1
  1. 1.Department of Entomology, University of California, Riverside, California 92521USA

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