Muffled olfactory and sensory cues from the reproductive stage soybean selectively reduce oviposition of a major polyphagous herbivore, fall armyworm(Spodoptera frugiperda)

Authors: GANDHAM, KRISHNARAO - University Of Arkansas; GAUTAM, MANISH - University Of Arkansas; George, Justin; Reddy, Gadi; KARIYAT, RUPESH - University Of Arkansas

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2024
Publication Date: 11/29/2024
Citation: Gandham, K., Gautam, M., George, J., Reddy, G.V., Kariyat, R. 2024. Muffled olfactory and sensory cues from the reproductive stage soybean selectively reduce oviposition of a major polyphagous herbivore, fall armyworm (Spodoptera frugiperda). Pest Management Science. 81:01-11. https://doi.org/10.1002/ps.8600.
DOI: https://doi.org/10.1002/ps.8600

Interpretive Summary: While the mother knows best/ preference, the performance hypothesis has been well tested in natural ecosystems, how these ecological principles differ in agroecosystems are is less explored. This study investigated the ovipositional preference and offspring performance of FAW across the vegetative and reproductive stages of soybean. We also examined how trichomes and volatile organic compounds (VOCs) of different phenological stages modulate oviposition behaviour. Electroantennogram (EAG) measurements assessed how olfactory responses are affected by volatiles at different growth stages. We found that gravid FAW preferred the vegetative stage when compared to the reproductive stage of soybean. Although there were no significant differences of VOC emissions and EAG response between photophase and scotophase, the vegetative stage exhibited significantly higher emissions and response than the reproductive stage during both the photophase and scotophase. Additionally, the reproductive stage had a low trichome density compared to the vegetative stage. In contrast to oviposition preference, no significant difference was observed in offspring performance between the vegetative and reproductive stages of soybean. This suggests suggesting that oviposition preference does not necessarily correlate with better offspring performance, which was confirmed through offspring mass and mass gain studies. Our results highlight the complexity of oviposition preference and off-spring performance.

Technical Abstract: In this study, we investigated the ovipositional preference and offspring performance of FAW across the vegetative and reproductive stages of soybean. We also examined how trichomes and volatile organic compounds (VOCs) of different phenological stages modulate oviposition behaviour. In addition, electroantennogram (EAG) measurements assessed how olfactory responses are affected by volatiles at different phenological stages. We found that gravid FAW preferred the vegetative stage when compared to the reproductive stage of soybean. Although there were no significant differences of VOC emissions and EAG response between photophase and scotophase, the vegetative stage exhibited significantly higher emissions and response than the reproductive stage during both the photophase and scotophase. Additionally, the reproductive stage had a low trichome density compared to the vegetative stage. In contrast to oviposition preference, no significant difference was observed in offspring performance between the vegetative and reproductive stages of soybean. This suggests suggesting that oviposition preference does not necessarily correlate with better offspring performance, which was confirmed through offspring mass and mass gain studies. Our results highlight the complexity of oviposition preference and off-spring performance. Olfactory and sensory cues from soybean at the reproductive stage selectively reduced oviposition of emerging herbivores, FAW. Collectively, we show that while mother knows best may not fit FAW-Soybean interaction, muffled volatile emission in reproductive stages, can have positive consequences for host success.