Plant species with higher chemical defenses enhance herbivore cellular immunity with differential effectiveness against two parasitoid species

Insect herbivores simultaneously experience bottom-up effects of plant defensive chemistry and the top-down effects of natural enemies. At the intersection of these effects are herbivore immune systems, herbivore traits that have largely been overlooked in studies of plant-insect interactions. Most previous studies have demonstrated compromised immunity of herbivores that feed on plants with higher defensive chemistry. Many studies have used embedded microfilaments or silica beads as proxies for parasitoid eggs. Yet, parasitoids may evade or suppress host immune responses by injecting venom, calyx fluid, or through modifications of their egg surface structure, necessitating studies that include all three trophic levels to obtain a complete picture of how plant traits may modulate herbivore immunity.Here we examined the effect of host plant species that differ in glucosinolate (anti-herbivore compounds produced by plants in the Brassicaceae) concentrations on the immune status of an herb..., ,