Resistance evolution in parasitoid biocontrol: understanding the rule, managing the exceptions

Area of Science:

• Ecology
• Evolutionary Biology
• Entomology

Background:

• Biological control (biocontrol) is an eco-friendly pest management strategy.
• Parasitoid wasps are common biocontrol agents, typically considered evolutionarily stable.
• Holt & Hochberg (1997) proposed principles explaining the rarity of pest resistance to biocontrol agents.

Purpose of the Study:

• To review case studies of biocontrol breakdown due to pest resistance since 1997.
• To evaluate these cases against the Holt & Hochberg framework.
• To propose updates to the framework and offer practical recommendations.

Main Methods:

• Literature review of post-1997 studies on parasitoid-based biocontrol failures.
• Comparative analysis of pest resistance evolution and parasitoid virulence.
• Framework evaluation and synthesis of findings.

Main Results:

• Resistance evolution, while rare, can lead to biocontrol failure.
• Breakdowns are more probable when pests have higher genetic variation than parasitoids.
• Parasitoid virulence evolution is a critical factor for long-term stability.

Conclusions:

• The Holt & Hochberg framework requires updates to incorporate new findings on resistance.
• Long-term biocontrol stability depends on both host and enemy evolutionary potential.
• Recommendations are provided for practitioners and regulators to mitigate resistance risks.