Impact of aquatic insect life stage and emergence strategy on sensitivity to esfenvalerate exposure

Environ Toxicol Chem. 2008 Aug;27(8):1728-34. doi: 10.1897/07-499.1. Epub 2008 Feb 11.


We investigated the impact of aquatic insect life stage and emergence strategy on sensitivity to esfenvalerate, a synthetic pyrethroid insecticide, using field-collected Brachycentrus americanus Banks (Trichoptera: Brachycentridae) and Cinygmula reticulata McDunnough (Ephemeroptera: Heptageniidae) insects. Final-instar C. reticulata emergence was observed for one week following three environmentally relevant, 48-h esfenvalerate exposures (0.005, 0.01, and 0.015 microg/L). Emergence was significantly depressed following exposure to esfenvalerate and resulted from an increase in nymph mortality during the emergence process. This experiment was duplicated for late-instar C. reticulata nymphs, which were similar in size to the final-instar nymphs but were not near emergence. Late-instar C. reticulata mayflies were approximately fivefold less sensitive to esfenvalerate exposures as gauged by one-week mortality rates. Brachycentrus americanus pupal mortality was significantly increased over that in controls following 48-h esfenvalerate exposures of 0.1 and 0.2 microg/L. These response concentrations correlated closely with those for case-abandonment rates of fourth-instar B. americanus larvae (a sublethal effect of esfenvalerate exposure). Pupal mortality rates were approximately 16-fold higher than those observed in larvae. Adult female egg weight as a percentage of total body weight was significantly decreased following pupal esfenvalerate exposures of 0.05, 0.1, and 0.2 microg/L. These findings suggest that exposure to esfenvalerate may impair hemimetabolous insect emergence behaviors and may decrease fecundity in holometabolous aquatic insects.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biological Assay
  • Body Size
  • Body Weight
  • Diet
  • Dose-Response Relationship, Drug
  • Female
  • Insecta
  • Insecticides / toxicity
  • Larva / drug effects*
  • Nitriles / toxicity*
  • Nymph / drug effects*
  • Pyrethrins / toxicity*
  • Time Factors
  • Water Pollutants, Chemical / pharmacology*


  • Insecticides
  • Nitriles
  • Pyrethrins
  • Water Pollutants, Chemical
  • fenvalerate