Why do predators attack parasitized prey? Insights from a probabilistic model and a literature survey

Area of Science:

• Ecology
• Behavioral Ecology
• Evolutionary Biology

Background:

• Predators and parasitoids frequently encounter parasitized prey during foraging.
• While outcomes for insect parasitoids are known, predator encounters with parasitized prey are less understood.
• The potter wasp (Delta dimidiatipenne) provisions nests with parasitized caterpillars, despite their low suitability.

Purpose of the Study:

• Investigate why female potter wasps collect parasitized caterpillars.
• Determine if predatory insects commonly incur fitness costs from encountering parasitized prey.
• Assess the conditions under which discriminating against parasitized prey is beneficial.

Main Methods:

• Developed a probabilistic mathematical model to predict the value of prey discrimination for potter wasps.
• Conducted a literature survey on how parasitism affects prey suitability and predator choice.
• Analyzed prey susceptibility, suitability, and predator prey choice in relation to parasitism status.

Main Results:

• The mathematical model indicated that discriminating against parasitized prey benefits potter wasp lifetime reproductive success only under specific conditions.
• Literature review revealed that encounters and consumption of parasitized prey are frequent.
• Quantification of the fitness consequences of these interactions remains rare in existing studies.

Conclusions:

• The profitability and ability of predators to discriminate against parasitized prey in natural settings may be limited.
• Further research is needed to quantify the outcomes of predator-parasitized prey interactions.
• Predatory insects may face fitness trade-offs when encountering parasitized prey.