Scared sick? Predator-pathogen facilitation enhances exploitation of a shared resource

Area of Science:

• Ecology
• Insect Ecology
• Biological Control

Background:

• Consumer diversity often increases resource use, attributed to resource partitioning.
• Pathogens and predators have distinct traits that may lead to complementary effects on shared prey.

Purpose of the Study:

• To investigate how predator-pathogen diversity affects herbivore suppression and plant damage.
• To determine if predator-pathogen pairings, rather than biodiversity alone, enhance control of the herbivorous beetle, *Leptinotarsa decemlineata*.

Main Methods:

• Manipulated predator and pathogen diversity in laboratory and field experiments.
• Assessed herbivore mortality and plant damage as outcomes.
• Tracked predator-pathogen complementarity throughout beetle development.

Main Results:

• Increased natural enemy species led to greater herbivore mortality and reduced plant damage.
• The pairing of predator and pathogen species, not overall biodiversity, significantly strengthened herbivore suppression.
• Predator exposure aboveground increased susceptibility to belowground pathogen infection, indicating weakened immune response.

Conclusions:

• Predator-pathogen combinations are highly effective in pest control, exceeding the impact of biodiversity alone.
• Predators facilitate pathogen efficacy by compromising the herbivore's internal defenses.
• This interaction highlights how natural enemies can enforce internal resource partitioning within prey individuals.