Induction of plant defenses: the added value of zoophytophagous predators

Abstract

Several biological control agents of the hemipteran insect families Miridae, Anthocoridae and Pentatomidae, as well as mites of the family Phytoseiidae are known as zoophytophagous predators, a subset of omnivores, which are primarily predaceous but also feed on plants. It has been recently demonstrated that zoophytophagous predators are capable of inducing defenses in plants through their phytophagy. Despite the vast fundamental knowledge on plant defense mechanisms in response to herbivores, our understanding of defense induction by zoophytophagous predators and applied implications is relatively poor. In this review, we present the physiological basis of the defense mechanisms that these predators activate in plants. Current knowledge on zoophytophagous predator-induced plant defenses is summarized by groups and species for the predators of economic importance. Within each group, feeding habits and the effects of their induced-plant defenses on pests and natural enemies are detailed. Also, the ecological implications of how the induction of defenses mediated by zoophytophagous predators can interact with other plant interactors such as beneficial soil microorganisms and plant viruses are addressed. Based on the above, we propose three approaches to exploit zoophytophagous predator-induced defenses in crop protection and to guide future research. These include using predators as vaccination agents, employing biotechnological approaches, as well as applying elicitors to elicit/mimic predator-induced defenses.

Effects of far‐red light on tritrophic interactions between the two‐spotted spider mite (Tetranychus urticae) and the predatory mite Phytoseiulus persimilis on tomato

“…Especially the effects on M. pygmaeus invite further research due to its omnivorous nature. Plant feeding by M. pygmaeus can induce plant defences against pests and pathogens, but can also lead to economic crop damage when densities are too high 43,44 . Changes in the plant's defensive status induced by FR light might change M. pygmaeus feeding behaviour between plants and arthropod prey and therefore its efficiency as biological control agent.…”

Effects of far‐red light on the behaviour and reproduction of the zoophytophagous predator Macrolophus pygmaeus and its interaction with a whitefly herbivore

“…However, the tritrophic interactions between plants, arthropod herbivores and M. pygmaeus are complex, and more research is required to understand how FR light shapes the ecological interactions between trophic levels. For example, plant feeding by mirid predators can induce plant defences and increase resistance to herbivores (Bouagga et al, 2020; Pappas et al, 2015; Pérez‐Hedo et al, 2022; Silva et al, 2022). Herbivores also avoid plants that have been exposed to M. pygmaeus (Zhang et al, 2019).…”

Potential of two omnivorous iolinid mites as predators of the tomato russet mite, Aculops lycopersici

“…However, as both iolinids feed on plant sap as well, their performance might be influenced by indirect effects associated with induced plant defenses triggered by other omnivorous natural enemies (e.g. zoophytophagous predators (Pérez-Hedo et al 2015;Pérez-Hedo et al 2022).…”