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Research Project: Biologically Based Techniques for Management of Vegetable Pests

Location: Vegetable Research

Title: Do heteropterans have longer molecular prey detectability half-lives than other predators? A test with Geocoris punctipes (Geocoridae) and Orius insidiosus (Anthocoridae).

Author
item Simmons, Alvin
item Weber, Donald
item Payton, Mark - Oklahoma State University
item Hu, Jing - Hu
item Greenstone, Matthew

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2015
Publication Date: 4/30/2015
Citation: Simmons, A.M., Weber, D.C., Payton, M.E., Hu, J.S., Greenstone, M.H. 2015. Do heteropterans have longer molecular prey detectability half-lives than other predators? A test with Geocoris punctipes (Geocoridae) and Orius insidiosus (Anthocoridae). Journal of Entomological Science. 50(2):99-105.

Interpretive Summary: Predatory arthropods, such as spiders, lacewings, ladybeetles and predatory true bugs, are important natural enemies of agricultural pests. They are small and often hidden, making it difficult to study the predator-prey process directly, so researchers rely on sophisticated molecular tools to detect the remains of insect prey in the bodies of predators. These tools are very powerful, but understanding the results are difficult because different types of predators digest prey food at different rates. The so-called detectability half-life was invented to help in the understanding of the data. Here we compare half-lives of different true bugs to see whether they are similar to use a common half-life value for all of them. The results show that because their half-lives cover such a large range of values, no single representative value can be used to represent them. This work is of interest to ecologists and insect pest managers.

Technical Abstract: Molecular gut-content analysis has revolutionized the study of predator-prey interactions and yielded important insights into arthropod community processes. However, the raw data produced by most gut-content assays cannot be used to assess the relative impact of different predator taxa on prey population dynamics. They must first be weighted by the detectability half-lives for molecular prey remains for each predator-prey combination. Otherwise, interpretations of predator impact will be biased toward those with the longest detectabilities. Molecular ecologists have noted taxonomic trends in the length of the half-life, in particular that they tend to be longer in spiders, stapylinids, and true bugs. Herein, we compare new data from feeding trials of two previously untested true bugs, Geocoris punctipes (Say) (Lygaeidae), and Orius insidiosus (Say) (Anthocoridae), with published data from four other heteropterans and three coleopterans. The objective of this study was to test the hypothesis that half-lives tend to be longer in predatory Heteroptera than in predators of other groups.