Meeting Abstract
Entomopathogenic nematodes (EPNs) are parasites that are able to kill insect pests and are widely used as biological control agents. During their lifecycle, EPN infective juveniles (IJs) leave their resource-depleted cadaver, and use chemosensory cues to locate a new host. Prenol is an odorant associated with already-colonized, resource- deficient hosts. To evaluate prenol as a dispersal cue, four species of EPNs from the family Steinernema were tested to identify if the odorant increased dispersal behavior in IJs across varying ages. Additionally we evaluated two types of assays- one aimed specifically at gauging dispersal and the other aimed at evaluating general chemotactic behavior. The viability of prenol as a dispersal cue varied between species and across the time points tested:4 hours, 24 hours, and 7 days post emergence from insect cadavers. We found that EPN IJs respond in a species-specific manner to prenol. Prenol increased dispersal behavior at 4 hours post collection for all species tested with the exception of S. riobrave, indicating that EPNs differ in their susceptibility to dispersal cues. At 24 hours post emergence, prenol acted as a viable dispersal cue for all species except S. feltiae, demonstrating that time post emergence affects dispersal. By 7 days post emergence, prenol’s ability to elicit IJ dispersal was weakened for all of the species tested expect S. carpocapsae. This may indicate that while S. carpocapsae is repelled by prenol, it may not be involved in dispersal behavior for this species. While the effect of prenol as a dispersal cue differed between species and were age dependent, repulsion behavior was fairly consistent between species and time post emergence. The difference suggests that our assays really are measuring different behaviors, and may assist in efforts to better utilize EPNs as biological control agents.
