Heritable variation in prey defence provides refuge for subdominant predators

Area of Science:

• Ecology
• Evolutionary Biology
• Predator-Prey Dynamics

Background:

• Generalist predators often coexist despite similar prey, suggesting niche differentiation.
• Heritable variation in prey defense mechanisms can create fine-grained niches.

Purpose of the Study:

• To demonstrate how variable prey defenses allow generalist predators to exploit distinct niches.
• To investigate the role of aphid toxicity in mediating predator-prey interactions and community structure.

Main Methods:

• Laboratory and open field experiments were conducted.
• Toxicity of Aphis craccivora clones against Harmonia axyridis and other ladybeetle species was assessed.
• Predator exploitation of toxic aphids under different community contexts was analyzed.

Main Results:

• Some Aphis craccivora clones exhibit toxicity specifically against the invasive Harmonia axyridis.
• Subdominant ladybeetle species successfully preyed on toxic aphids, benefiting from reduced competition.
• Aphid's narrow-spectrum toxicity acts as an anti-predator defense, contingent on the enemy community.

Conclusions:

• Heritable variation in prey defense drives niche differentiation among generalist predators.
• This mechanism can enhance the diversity and stability of predator communities, especially when invaded by dominant species.