Group Movement in Entomopathogenic Nematodes: Aggregation Levels Vary Based on Context.

Area of Science:

• Ecology
• Behavioral Ecology
• Entomology

Background:

• Population structure maintenance suggests within-species communication.
• Species-specific aggregations in mixed environments can reduce competition and promote coexistence.
• Entomopathogenic nematodes (EPNs) are important biological control agents.

Purpose of the Study:

• To investigate how movement and aggregation behavior of three EPN species change in isolation versus mixed-species arenas.
• To determine if EPNs exhibit species-specific aggregation signals.

Main Methods:

• Assessed movement and aggregation of Steinernema carpocapsae, S. feltiae, and S. glaseri in sand under single-species and mixed-species conditions.
• Mixed-species trials involved co-application in the center or separate corners of arenas.

Main Results:

• Each EPN species aggregated significantly when alone.
• In mixed-species trials, individual species showed reduced aggregation when co-applied in the same location.
• Conversely, species became more aggregated when introduced at separate corners, despite similar movement distances.

Conclusions:

• EPN aggregation is driven by species-specific signals that promote conspecific aggregation.
• These signaling mechanisms are disrupted when EPN species are mixed, particularly in commercial formulations.
• Understanding these behaviors is crucial for optimizing biological control strategies using EPNs.