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COMPARATIVE EMBRYONIC AND LARVAL DEVELOPMENTAL RESPONSES OF AN ESTUARINE SHRIMP (PALAEMONETES PUGIO) TO THE JUVENILE HORMONE AGONIST, FENOXYCARB.
Citation:
McKenney Jr., C L., G M. Cripe, S S. Foss, S. R. Tuberty, AND M D. Hoglund. COMPARATIVE EMBRYONIC AND LARVAL DEVELOPMENTAL RESPONSES OF AN ESTUARINE SHRIMP (PALAEMONETES PUGIO) TO THE JUVENILE HORMONE AGONIST, FENOXYCARB. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 47(4):463-470, (2004).
Impact/Purpose:
To evaluate the sensitivity of grass shrimp larvae to fenoxycarb
Description:
Grass shrimp (Palaemonetes pugio) were reared separately through both embryonic and total larval development during exposure to fenoxycarb at measured concentrations of <2.2 to 888 ug L-1. A fenoxycarb concentration of 888 ug L-1significantly (p<0.05) inhibited embryonic development to larval hatching and extended the embryonic developmental period from 11.9 to 12.7 days. Exposure to fenoxycarb concentrations less than or equal to 502 ?g L-1 had no significant (p=0.05) effect on complete embryonic development. Significantly fewer shrimp successfully metamorphosed to postlarvae while exposed through complete larval development to fenoxycarb concentrations greater than or equal to 4 ug L-1. Larval development of grass shrimp was, therefore, greater than two orders of magnitude more sensitive to this juvenile hormone (JH) agonist than was embryonic development. Viability of larvae developing in fenoxycarb was dose dependent. Development beyond third zoeal stage was significantly inhibited at fenoxycarb concentrations greater than or equal to 190 ug L-1, while development beyond fourth zoeal stage was inhibited by greater than or equal to 45 ug L-1. Fenoxycarb exposure of developing larvae did not alter either the duration of total larval development or the total number of larval stages prior to metamorphosis. Rearing of fenoxycarb-exposed embryos through larval development without further exposure had no significant effect on number of larval stages, larval development rate or metamorphic success of larvae. Similarities in the sensitivity of grass shrimp larvae and mosquito larvae to fenoxycarb suggests that the use of a bioassay protocol measuring the metamorphic success of crustacean larvae would be a valuable adjunct to the hazard assessment of newly developed
pesticides which target endocrine control of metamorphosis in insects and possibly other endocrine-disrupting xenobiotics as well.