Impact of a generalist predator, the spined soldier bug Podisus maculiventris (Heteroptera: Pentatomidae) on tomato induced defenses

The activation of plant anti-herbivory defense mechanisms may require the original detection of actual threat by the plant. When initiating contact with a host plant, insects may release a set of physical and/or chemical cues that can be recognized by the plant as signals for a significant risk of damage. In some herbivorous species, behaviors such as feeding, oviposition or just locomotion have been shown to potentially elicit a defense reaction in plants. However, little is known on a possible effect of the presence of beneficial insects, such as generalist predators, on the induction of plant defenses.

In this study, we examine the impact of the presence of the predatory stinkbug Podisus maculiventris on the induction of selected tomato genes associated to the jasmonic acid, salicylic acid and ethylene defense pathways. We use RQ-RT-PCR to quantify changes in defense gene expression in response to Podisus maculiventris. We analyze the effects on plant defenses in response to factors such as the insect gender, life stage, density and time of presence on the leaf, and will discuss the possible agro-ecological implications of our findings.