Ecotoxicology

, 14:313

Developmental Responses of a Terrestrial Insect Detritivore, Megaselia scalaris (Loew) to Four Selenium Species

  • Peter D. Jensen
  • Maria D. Rivas
  • John T. Trumble
Article

DOI: 10.1007/s10646-003-6368-x

Cite this article as:
Jensen, P.D., Rivas, M.D. & Trumble, J.T. Ecotoxicology (2005) 14: 313. doi:10.1007/s10646-003-6368-x

Abstract

Megaselia scalaris (Loew) (Diptera: Phoridae) is an important and ubiquitous terrestrial detritivore that consumes both animal and plant material. Because both plants and animals convert selenium pollutants into various forms, the relative toxicities of ecologically relevant concentrations of sodium selenate, sodium selenite, seleno-L-methionine, and Se-(methyl) selenocysteine hydrochloride to larvae were assessed in diet bioassays. In addition, ovipositional preferences of adults and developmental effects on the eggs and larvae were measured. With chronic exposure selenocysteine was the most toxic of the selenium species to the larvae (LC50: 83 μg/g wet weight), followed by seleno-L-methionine (LC50: 130 μg/g), selenate (LC50: 258 μg/g), and selenite (LC50: 392 μg/g). Ovipositing females did not discriminate between the highest treatment concentrations of any of the pollutants as compared to the controls, indicating a lack of avoidance behavior. Larval development time was significantly increased with exposure to selenate at 100 μg/g wet weight and above, selenite at 300 μg/g and above, and at 50 μg/g and 25 μg/g and above for seleno-L-methionine and selenocysteine respectively. Pupal development was not affected by any of the selenium treatments. Significant differences between male and female adult eclosion times were observed, with females eclosing later than males as selenium concentrations increased. Significant decreases in larval survival relative to controls occurred at the lowest treatment tested (100 μg/g) for both selenate and selenite and at 100 μg/g for seleno-L-methionine, and 50 μg/g for selenocysteine. The population level implications of lack of avoidance of contaminated food, and the effects of increased development times, reduced survivorship, and non-synchronized male and female emergence are discussed.

Keywords

sodium selenate sodium selenite seleno-L-methionine and selenocysteine Megaselia scalaris 

Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  • Peter D. Jensen
    • 1
  • Maria D. Rivas
    • 1
  • John T. Trumble
    • 1
  1. 1.Department of EntomologyUniversity of CaliforniaRiversideUSA