Meeting Abstract
Entomopathogenic nematodes (EPNs) are insect parasites used as biological control agents. EPN infective juveniles (IJs)are free-living and employ host-seeking behaviors to locate suitable hosts for infection. The health of a potential host greatly impacts the success and reproductive potential of a newly-invading IJ. Infecting a naïve host incurs the risk of failure to overcome the immune response and the possibility that mates may not be encountered. An infected host includes several benefits – reduced host immunity and potential mates. Resources are depleted at late stages of infection, thus impeding the success of a newly invading IJ. We predicted that chemosensory information would enable IJs to determine the infection status of potential hosts. To study this, we examined the attraction of Steinernema species (S. carpocapsae, S. feltiae, S. glaseri, and S. riobrave) to naïve and infected hosts. We found that EPNs can differentiate between naïve and infected hosts, and that host attractiveness changes over time in a species-specific manner. We used gas chromatography, and mass spectrometry to identify odorants that may relay information about potential host health and infection status. Among the odorants we identified, we selected 2-buten-1-ol-3-methyl (prenol) and 3-hydroxy-2-butanone (acetoin) for further behavioral study. Both of these odorants were repulsive to S. glaseri and S. riobrave IJs in a dose-dependent manner. We also found that prenol elicits attraction behaviors from larval stage Drosophila melanogaster, suggesting that host-associated odors may have several roles, such as signaling avoidance and dispersal, and acting as an attraction signal to new hosts.
