U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Vegetable Crops Research: Madison, WI
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    ScientistsSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Madison, Wisconsin Vegetable Crops Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Steffan, Shawnitem
                                            CHIKARAISHI, YOSHITO - Japan Agency For Marine-Earth Science And Technology (JAMSTEC)item
                                            Horton, Daviditem
                                            Miliczky, Eugeneitem
                                            Zalapa, Juanitem
                                            JONES, VINCENT - Washington State Universityitem
                                            OHKOUCHI, NAOHIKO - Japan Agency For Marine-Earth Science And Technology (JAMSTEC)
  Submitted to: Entomological Society of America Annual Meeting North Central Branch
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 1/27/2014
                                    Publication  Date: 3/9/2014
                                    Citation: Steffan, S.A., Chikaraishi, Y., Horton, D.R., Miliczky, E., Zalapa, J.E., Jones, V., Ohkouchi, N. 2014. Trophic spectra under the lens of amino acid isotopic analysis [abstract]. Entomological Society of America Annual Meeting North Central Branch.Interpretive Summary:
                                Technical Abstract: Recent advances in compound specific isotopic ratio analysis (CSIRA) have allowed researchers to measure trophic fractionation of 15N in specific amino acids, namely glutamic acid and phenylalanine. These amino acids have proven useful in food web studies because of the wide and consistent disparity in their respective fractionation tendencies. In controlled feeding trials, we used CSIRA to confirm the accuracy of the Chikaraishi C3-plant equation for trophic levels 1 through 4. We then collected wild arthropods from an old-field site, and each specimen was analyzed using both the Chikaraishi method and the conventional bulk-15N method. Regression analysis characterized the relationship between these two methods, allowing us to convert bulk-15N values into trophic level estimates (among the many specimens not analyzed via CSIRA). This approach facilitated greater sample sizes and thereby permitted investigations of trophic spectra and functional diversity. We show that species often thought to be strict herbivores were true omnivores, and certain carnivore species were actually pests of crop production. Thus, our study is the first to reveal which species are likely to be beneficial for crop protection, and which are not.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov