Effect of inorganic and organic forms of selenium supplementation on development of larval Heliothis virescens |
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Authors: | Holly J R Popham Kent S Shelby |
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Institution: | US Depatment of Agriculture–Agricultural Research Service (USDA-ARS), Biological Control of Insects Research Laboratory, 1503 South Providence Rd., Columbia, MO 65203, USA |
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Abstract: | Selenium (Se) is an essential micronutrient for vertebrates though little is known about the effects on insects. Herbivorous insect larvae acquire Se from plant tissues in the inorganic form of sodium selenate and sodium selenite, and in the organic form of selenoamino acids, selenomethionine, and selenocystine. In this study, we document the effects of dietary supplementation with sodium selenite, sodium selenate, selenocystine, selenomethionine, and selenized yeast on the developmental rate of Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae). Larvae tolerated high levels of Se (500 µg g?1 Se) as sodium selenate and to a lesser extent as selenocystine. Lower levels of sodium selenite (>1 µg g?1 Se) caused increased mortality, reduced rates of pupation, more pupal/adult intermediates, and reduced adult emergence. Selenomethionine proved toxic to larvae at levels above 25 µg g?1 Se, significantly delaying pupation and raising mortality. Provision of Se as selenized yeast, which contains primarily selenomethionine, was also extremely detrimental to larval development and survival. The results indicate that the impact of dietary Se supplement for insects may differ from vertebrates. |
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Keywords: | sodium selenite sodium selenate selenocystine selenomethionine Sel-Plex? Lepidoptera Noctuidae |
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