The mirid predator Macrolophus basicornis smells and avoids eggs of Tuta absoluta parasitized by Trichogramma pretiosum

Abstract

Biological control, which uses natural enemies to reduce pest populations, is a non-polluting powerful method to manage impacts of (invasive) pests. Currently, polyphagous mirid predators are increasingly used in commercial, augmentative biological control. Information about their foraging behaviour is essential, especially if one intends to use several natural enemies for control of one or more pests in a crop, to detect if negative intraguild effects occur. We studied a case of intraguild predation (IGP) involving a predator, Macrolophus basicornis, of the worldwide invasive South American tomato leaf miner Tuta absoluta, and explored how this predator deals with prey parasitized by Trichogramma pretiosum. Behavioural observations show that M. basicornis predators contacted significantly fewer old, parasitized eggs of T. absoluta than recently parasitized ones. Olfactometer tests revealed that predators could smell differences between volatiles of tomato leaves infested with eggs of different quality to locate suitable prey. They preferred volatiles from leaflets with unparasitized eggs above control leaflets, and, moreover, preferred volatiles from leaflets with recently parasitized eggs over volatiles of leaflets with 5-day old parasitized eggs. When predators and parasitoids are used together to control T. absoluta, parasitoids should be introduced days before predators to prevent high levels of IGP.