Low moisture stress influences plant volatile emissions affecting herbivore interactions in tomato, Solanum lycopersicum.
Frequently changing climatic conditions can cause recurring droughts which often subject plants to tremendous amounts of stress, leaving biologists to wonder about its impact on the associated herbivores and their interactions with host plants. The present study was aimed at assessing the impact of low moisture stress on herbivore-plant interactions using tomato and its associated herbivores (leaf miner, Tuta absoluta and sap feeder, Bemisia tabaci). The leaf miner T. absoluta preferred tomato plants exposed to moderate drought stress compared to severely drought stressed or healthy plants while the sap feeder B. tabaci preferred healthy tomato plants that were irrigated regularly over others. Our study uncovers few intriguing aspects of low moisture stress on herbivore-host interactions and also highlights that this influence may vary depending upon the herbivore feeding guild. The volatile profiles of tomato plants were found to differ significantly when subjected to varied degrees of low moisture stress. Such changes in plant's volatile emissions may in turn alter its associated herbivore's behavioural perspective as observed in T. absoluta and B. tabaci. Reduced amounts of caryophyllene, humulene, 3-carene, myristic acid, and γ-butyl-γ-butyrolactone might be what aids T. absoluta and B. tabaci in gauging the drought stress status of a host plant. Further, the presence of chemical cues such as α-pinene, m-cymene, and ethyl benzaldehyde might signal T. absoluta moths of severely stressed plants. Similarly, the presence of undecane, ethyl benzaldehyde, n-hexadecanoic acid might aid whiteflies in identifying plants reeling under low moisture stress.