Conclusion
The presence of salt as an abiotic stressor in agricultural soils is a
serious problem, with research focusing primarily on plant tolerance to
salt. However, the inclusion of biotic stressors, such as insect pest
infestations, leads to varied plant responses. Understanding plant
responses under interacting stresses is vital to developing better crop
varieties and insect control. Moreover, salinity-influenced changes to
plant quality and composition affect insect herbivores feeding on these
plants.
In our study, we observed that a notorious pest, Helicoverpa zea,performed poorly on salinity-affected tomato plants. Although our study
focused exclusively on a leaf-chewing, generalist herbivore, it would be
interesting to investigate how different insect feeding guilds
(specialist leaf chewers, phloem feeders, gall makers, leaf miners,
etc.) respond to soil salinization. Our work demonstrates the need to
study how insect pests are indirectly affected by environmental changes,
as this has implications for their survival and performance in
agricultural settings. Thus, along with deciphering the molecular basis
behind plant responses to multiple stresses, we also need to understand
their ecological implications so that we can formulate accurate IPM
strategies.
For future work, we wish to investigate salinity-based changes to plant
indirect defenses. Salinity can influence other trophic levels in
plant-insect interactions, including predators, parasitoids, and local
microbiota. Insect quality as a food source for predators or a potential
host for parasitoids and microbes drives predator and parasitoid
choices, which would in turn affect insect population dynamics in the
field.