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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #406448

Research Project: Novel Approaches for Managing Key Pests of Peach and Pecan

Location: Fruit and Tree Nut Research

Title: Group movement in entomopathogenic nematodes: aggregation levels vary based on context

item STEVENS, GLEN - University Of Idaho
item MUHAMMAD, USMAN - Michigan State University
item GULZAR, SEHRISH - University Of Agriculture, Faisalabad
item STEVENS, ASA - University Of Idaho
item PIMENTEL, ELENOR - University Of Idaho
item ERDOGAN, HILAL - University Of Idaho
item SCHLIEKELMAN, PAUL - University Of Georgia
item KAPLAN, FATMA - Pheronym, Inc
item Alborn, Hans
item Shapiro Ilan, David
item LEWIS, EDWIN - University Of Idaho

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2024
Publication Date: 2/2/2024
Citation: Stevens, G., Muhammad, U., Gulzar, S., Stevens, A., Pimentel, E., Erdogan, H., Schliekelman, P., Kaplan, F., Alborn, H.T., Shapiro Ilan, D.I., Lewis, E.E. 2024. Group movement in entomopathogenic nematodes: aggregation levels vary based on context. Journal of Nematology. 0022/2011.

Interpretive Summary: Beneficial nematodes (also known as entomopathogenic nematodes) are small round worms that are used as natural biopesticides. Unlike many chemical insecticides that are toxic to humans, other nontarget organisms, and the environment, beneficial nematodes only kill insects and are considered safe to the environment. To increase our ability to use the beneficial nematodes in an efficacious manner for pest control, it is important to understand their basic behavior. In previous research, we discovered that the nematodes move together in the soil when hunting for insects, like a pack of wolves seeking their prey. In the current study, we investigated what happens when two different species of nematodes encounter each other in soil. If two nematode species were applied together to the same location, then the level of aggregative movement (moving together) within each species decreased. However, if two nematodes were applied each at a different location and they encountered each other afterwards, the level of aggregation increased. This study adds to our fundamental understanding of nematode ecology and movement behavior.

Technical Abstract: Maintenance of aggregated population structure implies some within-species communication. In mixed species environments, species-specific aggregations may reduce interspecific competition and thereby promote multi-species coexistence. We studied whether movement and aggregation behavior of three entomopathogenic nematode species changed when alone compared to mixed-species arenas. Movement and aggregation of Steinernema carpocapsae, Steinernema feltiae and Steinernema glaseri were assessed in sand. All three species demonstrated significant aggregation when applied alone, confirming prior research. Mixed-species trials involved adding two species of nematodes, either combined in the center of the arena or at separate corners. We discovered that while individual species tended to become less aggregated than in single-species conditions when co-applied in the same location, they became more aggregated when applied in separate corners. This increased aggregation in separate corner trials occurred even though the nematodes moved just as far when mixed as they did when alone. These findings suggest that maintenance of multiple entomopathogenic nematode species within the same habitat is driven at least in part by species-specific signals that promote conspecific aggregation, and when the species are mixed together (as occurs in commercial formulations involving multiple EPN species) these signaling mechanisms are muddled.