Revealing the Diet of Generalist Insect Predators in Strawberry Fields: Not Only Pests, But Other Predators Beware

Area of Science:

• Agricultural Entomology
• Ecology
• Molecular Ecology

Background:

• Generalist invertebrate predators provide essential ecosystem services, particularly in organic agriculture, by aiding pest management.
• DNA-based methods have revolutionized the study of predator diets and food web interactions in natural environments.

Purpose of the Study:

• To investigate the diets of generalist insect predators in Florida organic strawberry fields using next-generation sequencing (NGS).
• To assess the contribution of these predators to pest suppression and biological control services.

Main Methods:

• Utilized MiSeq next-generation sequencing (NGS) with universal arthropod primers to analyze predator diets.
• Collected and analyzed 105 predator samples from organic strawberry fields over the 2017–2018 growing season.
• Identified prey items by matching DNA sequences to arthropod families, categorizing them as pest, nonpest, or predator families.

Main Results:

• Identified 12 predator insect taxa, with Geocoris spp. being the most abundant early in the season.
• DNA analysis matched predator sequences to 44 arthropod families, including 17 pest families (e.g., Drosophilidae) and 17 predator families (e.g., Dolichopodidae).
• Observed varying prey diversity among predators, with Chrysoperla spp. consuming more prey early on, while others engaged in significant intraguild predation.

Conclusions:

• Predators in organic strawberry systems consume a diverse range of prey, including other predators (intraguild predation).
• These generalist predators actively contribute to suppressing pest populations, providing a valuable biological control service in Florida's organic strawberry production.