American Society of Naturalists

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“The behavioral type of a top predator drives the short-term dynamic of intraguild predation”

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Radek Michalko and Stano Pekár

The behavioral types and abundances of interacting species can interactively determine the food-web dynamics

The timid / choosy predator (<i>Philodromus</i>) consuming the pest (<i>Cacopsylla</i>).<br />(Credit: Stano Pekár)
The timid / choosy predator (Philodromus) consuming the pest (Cacopsylla).
(Credit: Stano Pekár)

Arthropod predators, like humans, show individual variation in behavior. For example, some individuals are choosy and pick up only certain prey, while others catch whatever they can overcome. Individual predators can also differ in their foraging aggressiveness, for instance killing more or fewer prey during a foraging bout. Consequently, the behavioral differences among individual predators (i.e. behavioral types) can shape the dynamic of interactions with pests and other predators occurring in an agroecosystem.

Radek Michalko and Stano Pekár, researchers from Mendel and Masaryk Universities in Brno, Czech Republic, tried to disentangle the complex interactions among predators and pests in a pear orchard in order to reveal how the behavioral type of the predator can be used to improve pest control by natural enemies. They investigated the behavioral differences of the top predator and their effect on foraging efficiency against other predators and psylla pests. And then they used simulations of a mathematical model to predict the dynamic of interactions in the system during the winter and spring.

They find that the timid individuals kill fewer pests and are choosy as they prefer pests to other predators. In contrast, the aggressive individuals kill more pests and do not prefer pests to other predators. Consequently, the agroecosystem with aggressive predatory individuals is generally more effective in pest control when other predators are less abundant, while the agroecosystem with timid predatory individuals is more effective when other predators are more abundant. The authors suggest that the aggressive / non-choosy predators might be useful for biocontrol in annual agroecosystems (e.g., fields of grain), while the timid / choosy predators might rather be useful in perennial agroecosystems (e.g., orchards). Read the Article