IMPACT OF AQUATIC INSECT LIFE STAGE AND EMERGENCE STRATEGY ON SENSITIVITY TO ESFENVALERATE EXPOSURE

• Published in: Environmental toxicology and chemistry Vol. 27; no. 8; pp. 1728 - 1734
• Main Authors: Palmquist, K.R, Jepson, P.C
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Periodicals, Inc 01.08.2008; Blackwell Publishing Ltd
• Subjects: Adults; Agricultural production; Animals; Aquatic insects; Aquatic life; Banks; Biological Assay; Body Size; Body Weight; Brachycentridae; Brachycentrus americanus; Cinygmula reticulata; Control equipment; Copyrights; Correlation; developmental stages; Diet; Documents; dose response; Dose-Response Relationship, Drug; Emergence; Emergence strategy; Environmental conditions; environmental exposure; Environmental health; Ephemeroptera; esfenvalerate; Exposure; Fecundity; Female; Females; Health services; Heptageniidae; insect behavior; insect development; Insecta; Insecticides; Insecticides - toxicity; Insects; Larva - drug effects; Larvae; Mortality; Nitriles - toxicity; Nymph - drug effects; nymphs; Presses; pupae; Pyrethrins - toxicity; Pyrethroids; Reproduction; Sensitivity; Skin; Strategy; Surface water; Synthetic pyrethroids; Time Factors; Toxicology; Trichoptera; Water Pollutants, Chemical - pharmacology; water pollution
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1897/07-499.1

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 μg/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 μg/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 μg/L. These findings suggest that exposure to esfenvalerate may impair hemimetabolous insect emergence behaviors and may decrease fecundity in holometabolous aquatic insects.