effect of plant identity and the level of plant decay on molecular gut content analysis in a herbivorous soil insect

• Published in: Molecular ecology resources Vol. 13; no. 1; pp. 75 - 83
• Main Authors: Wallinger, Corinna, Staudacher, Karin, Schallhart, Nikolaus, Peter, Eva, Dresch, Philipp, Juen, Anita, Traugott, Michael
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.01.2013; Blackwell; Wiley Subscription Services, Inc
• Subjects: Agriotes; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Chloroplast DNA; click beetle; Coleoptera - physiology; digestion; digestive system; DNA Primers - genetics; DNA, Chloroplast - genetics; Electrophoresis; feeding experiment; Flowers & plants; food choices; forbs; Fundamental and applied biological sciences. Psychology; Gastrointestinal Contents - chemistry; General aspects; Genetics of eukaryotes. Biological and molecular evolution; Germany; grasses; Herbivores; Herbivory - physiology; insect larvae; Larva - physiology; legumes; palatability; phytophagous insects; Plant Roots - genetics; Plant Roots - metabolism; plant tissues; polymerase chain reaction; Polymerase Chain Reaction - methods; Population genetics, reproduction patterns; Regression Analysis; Resource; roots; soil; soil insects; Species Specificity; Synecology; trnL; wireworm; click beetle; Agriotes; Herbivorous; Coleoptera; Elateridae; Insecta; trnL; Feeding; Soils; wireworm; Diet; Arthropoda; Invertebrata; feeding experiment; Content analysis
• ISSN: 1755-098X; 1755-0998
• DOI: 10.1111/1755-0998.12032

Plant roots represent an important food source for soil‐dwelling animals, but tracking herbivore food choices below‐ground is difficult. Here, we present an optimized PCR assay for the detection of plant DNA in the guts of invertebrates, using general plant primers targeting the trnT‐F chloroplast DNA region. Based on this assay, we assessed the influence of plant identity on the detectability of ingested plant DNA in Agriotes click beetle larvae. Six different plant species were fed to the insects, comprising a grass, a legume and four nonlegume forbs. Moreover, we examined whether it is possible to amplify DNA of decaying plants and if DNA of decayed plant food is detectable in the guts of the larvae. DNA of the ingested roots could be detected in the guts of the larvae for up to 72‐h post‐feeding, the maximum digestion time tested. When fed with living plants, DNA detection rates differed significantly between the plant species. This may be ascribed to differences in the amount of plant tissue consumed, root palatability, root morphology and/or secondary plant components. These findings indicate that plant identity can affect post‐feeding DNA detection success, which needs to be considered for the interpretation of molecularly derived feeding rates on plants. Amplification of plant DNA from decaying plants was possible as long as any tissue could be retrieved from the soil. The consumption of decaying plant tissue could also be verified by our assay, but the insects seemed to prefer fresh roots over decaying plant material.