Biodiversity enhances the multitrophic control of arthropod herbivory

Abstract

Arthropod herbivores cause substantial economic costs that drive an increasing need to develop environmentally sustainable approaches to herbivore control. Increasing plant diversity is expected to limit herbivory by altering plant-herbivore and predator-herbivore interactions, but the simultaneous influence of these interactions on herbivore impacts remains unexplored. We compiled 487 arthropod food webs in two long-running grassland biodiversity experiments in Europe and North America to investigate whether and how increasing plant diversity can reduce the impacts of herbivores on plants. We show that plants lose just under half as much energy to arthropod herbivores when in high-diversity mixtures versus monocultures and reveal that plant diversity decreases effects of herbivores on plants by simultaneously benefiting predators and reducing average herbivore food quality. These findings demonstrate that conserving plant diversity is crucial for maintaining interactions in food webs that provide natural control of herbivore pests.

The hidden role of multi-trophic interactions in driving diversity-productivity relationships

“…In our simulations, generalism is constraint by predator-prey body-mass ratios known from aquatic and belowground ecosystems (Schneider et al 2016). Regardless, they are sufficient to reproduce the decreasing influence of herbivores on primary production as producer diversity increases that is common to forests, grasslands, and agroecosystems alike (Barnes et al 2020;Wan et al 2020;Jactel et al 2021). We find that animals largely influence net diversity effects by reducing primary production in monocultures (Barry et al 2018).…”

High Variability in Pre-Oviposition Time Independent of Diet Available at Eclosion: A key Reproductive Trait in the Ladybird Beetle Harmonia axyridis (Coleoptera: Coccinellidae) in Its Native Range

“…Insect predators play a crucial role in diversified agroecosystems by naturally regulating pests (e.g., [ 1 ]). Understanding their ecology is key to developing strategies that favor their presence and proliferation to facilitate biological control [ 2 , 3 ].…”

Multifunctionality of belowground food webs: resource, size and spatial energy channels

“…These functions can be related to the top-down control of the entire food-web, a specific energy channel, or a specific consumer. This can be quantitatively assessed by calculating the ratio of the outgoing energy flux from a food-web node to the biomass of the node (Barnes et al, 2020) or by calculating the ratio of the energy fluxes at the bottom and at the top of the foodweb. Such "energy flux pyramids" of primary, secondary and third-level trophic interactions can vary substantially not only across food webs, but also within a food-web across different energy channels (Fig.…”

“…7). The sum of outgoing energy fluxes from a pest can be used to quantify its top-down control (Barnes et al, 2020) and identify potential key biocontrol agents (B). The sum of incoming energy fluxes to a bird (or birds) can be used to identify potential animal groups and basal resources that play the most important role in its nutrition (C).…”