Uptake of dietary selenium by laboratory and field feeding Podisus maculiventris (Heteroptera: Pentatomidae)

Authors: Shelby, Kent; Coudron, Thomas; Morales Ramos, Juan

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2016
Publication Date: 3/30/2017
Citation: Shelby, K., Coudron, T.A., Morales Ramos, J.A. 2017. Uptake of dietary selenium by laboratory and field feeding Podisus maculiventris (Heteroptera: Pentatomidae). Florida Entomologist. 100(1):199-202. https://doi.org/10.1653/024.100.0134.
DOI: https://doi.org/10.1653/024.100.0134

Interpretive Summary: The spined soldier bug is a beneficial predatory stinkbug commercially available for biological control of pest insects in alfalfa, corn, soy, vegetables and orchards. The spined soldier bug is exposed to a wide variety of nutritive metals based upon the soil type, plant species, and insect prey items that it consumes. Selenium is an essential element present in soil that is accumulated by plants, and subsequently by animals which consume the plants. In this study we measured the levels of selenium taken up by spined soldier bugs from three types of diets: an artificial diet, a diet of insectary reared caterpillars, and a diet of alfalfa weevils collected directly from the field, as well as alfalfa foliage. Selenium accumulation by spined soldier bugs from insectary-reared caterpillars as prey did not occur. However spined soldier bugs accumulated selenium from the field-reared weevil and from the artificial diet. This information, along with previously published information on the negative effects of selenium accumulation by the spined soldier bug shows that the ability to bioaccumulate selenium may depend upon the type of food or prey items available and that selenium levels in the soil, fertilizers, and biofortified crops could impact the effectiveness of biological control agents in the field. This information will help scientists and producers correctly extrapolate control measures based on field conditions such as the type of soil and crop to use an insect predator in the field.

Technical Abstract: Podisus maculiventris (Say) is a generalist pentatomid predator commercially available for augmentative biological control of pest insects in a variety of crop and orchard systems. P. maculiventris is exposed to a wide variety of micronutrients based upon the soil type, plant, and insect prey items consumed. Bioaccumulation of Se by P. maculiventris fed insectary-reared T. ni larval prey was not statistically significant. However P. maculiventris collected from the field that had been feeding primarily on Alfalfa weevils, and those fed an artificial liver-based diet showed highly significant bioaccumulation of Se. This is the first report of biomagnification of a trace element across three trophic levels involving P. maculiventris.