Effects of Simulated and Insect Herbivory on Total and Protein Percipitable Phenolic Concentrations of Two Legumes

Effects of Simulated and Insect Herbivory on Total and Protein Percipitable Phenolic Concentrations of Two Legumes

Summary

A comparison of protein precipitable polyphenolic (PPP) concentrations after simulated and insect herbivory suggests that Desmodium paniculatum and Lespedeza cuneata do not distinguish between the types of herbivory. Both species, however, decreased leaf PPP concentrations as herbivory intensity increased. Protein binding ability of PPP also declines with herbivory intensity, especially when the plant is entirely defoliated.

Objectives/Performance Targets

Determine how varying levels of herbivory (simulated and by differential grasshopper) and plant ontogeny affect:

1. Phenolic concentration of leaves
2. Nutrient concentration (nitrogen, carbon, and dry matter) of leaves
3. Dry matter, phenolic and N yield of regrowth

Accomplishments/Milestones

To date, plants have been grown, exposed to herbivory, and partially analyzed in the laboratory. Remaining work includes finalizing laboratory and statistical analyses and preparing a manuscript for publication.

Impacts and Contributions/Outcomes

This research will aid producers in understanding how their forages respond to defoliation, whether by mechanical or by animal means. Forages high in condensed tannins have both positive and negatives in ruminant production. They can reduce livestock feed efficiency if present in concentrations of biologically active condensed tannins. Recent research, however, indicates that there are more positives and negatives, including suppressing internal and external parasite development, mitigating rumen methane emissions, and increasing protein bypass in the rumen.

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