Combined effects of arthropod herbivores and phytopathogens on plant performance

Abstract

Summary1. Many plants are simultaneously attacked by arthropod herbivores and phytopathogens. These may affect each other directly and indirectly, enhancing or reducing the amount of plant resources they each consume. Ultimately, this may reduce or enhance plant performance relative to what should be expected from the added impacts of herbivore and pathogen when they attack alone.2. Previous studies have suggested synergistic and antagonistic impacts on plant performance from certain combinations of arthropods and pathogens, for example, synergistic impacts from necrotrophic pathogens together with wounding arthropods because of facilitated infection and antagonistic impacts from induction of pathogen resistance by sucking herbivores. 3. We compiled published studies on the impact of plant-herbivore-pathogen interactions on plant performance and used meta-analysis to search for consistent patterns of impacts among plant, herbivore and pathogen characteristics and experimental conditions, and to test the suggested hypotheses on synergistic or antagonistic impacts. 4. None of the hypotheses based on proximate interactions between arthropods and pathogens were supported by our analysis; in contrast, the patterns we found were related to plant traits and experimental conditions. 5. Our results suggest that immediate loss of resources from interactions between arthropod herbivores and pathogens is generally moderated by compensation to an extent where there are no interactive effects on plant performance. However, as interactive impacts also differed among environments and parasite manipulation methods, this suggests that the ability of plants to compensate such losses may depend on environmental conditions and probably also overall infection load.

Plant-Mediated Systemic Interactions Between Pathogens, Parasitic Nematodes, and Herbivores Above- and Belowground

“…Such indirect, plant-mediated interactions have important consequences for both the plant and its associated community. From the perspective of the individual plant, interactions between its consumers are important, as they can result in synergistic or antagonistic effects on plant fitness (51). From the perspective of the consumers, such interactions are important because the presence of other consumers affects their success in colonizing and exploiting the plant.…”

Three‐way interactions between plants, microbes and insects

“…Hauser et al . () in this issue perform a meta‐analysis of the combined effects of plant pathogens and insect herbivores on plant performance. They analyse patterns of additive, synergistic and antagonistic effects of different guilds of insect herbivores and pathogens on plant performance by comparing their combined impact with their impacts as single attackers.…”

Vector and nonvector insect feeding reduces subsequent plant susceptibility to virus transmission

“…A meta‐analysis on the published studies of the impact of plant–herbivore–pathogen interactions up to 2012 did not reveal any consistent patterns of impacts among plant, herbivore and pathogen characteristics (Hauser et al ., ). On top of the peculiarity of the species/strains involved in each system of a tripartite interaction, the environmental conditions, such as water availability (Davis et al ., ), may alter the direct and indirect interactions considerably.…”