Connecting detritivores and plant community dynamics in pasture mesocosms

Decomposers like dung beetles (Scarabaeidae) are valuable agents of waste removal and important nutrient cyclers. By incorporating waste, particularly animal manures, dung beetles and other detritivores can change the availability and location of nutrients for plants. The resulting changes in soil nutrients are likely to affect dominance of different plant species. Simultaneously, there is good evidence that manure applied as a fertilizer has benefits for plant resilience, especially against pests. Because manure can reduce herbivore damage, and dung beetles alter nutrient cycling in pasture ecosystems, we asked: how do dung beetle and earthworm activity affect different species in a pasture community relative to each other, and how does dung beetle activity influence plant damage from herbivores? To answer this question, we grew a mixture of five common pasture species (ryegrass, orchard grass, white clover, red clover, dandelion) in mesocosms on the West Virginia Animal Sciences Farm, fertilized each with dung, and established Onthophagus hecate (tunneler, Scarabaeidae: Scarabaeinae), Oscarinus rusicola (dweller, Scarabaeidae: Aphodiine), and earthworms (Eisenia fetida) in these pats. After several weeks, we measured the relative growth of different plant species. We also measured fall armyworm (Spodoptera frugiperda) performance and damage on excised leaf tissue from pots with different species of decomposers. These data provide insight to better understand how detritivores can influence above-ground plant dynamics.