Comparison of resistance to pest infestation between native and exotic mangrove species

Pest infestation is one of the critical biotic threats to mangrove ecosystem stability. Early observations of infestation-induced damage and plant resistance could reveal the initial status of insect attacks. However, the differences between the pest resistance of native and exotic mangrove species remain poorly addressed. Here, we collected leaf photosynthetic, nutritional, morphological, and optical traits from four native and two exotic mangrove species in a subtropical mangrove ecosystem under healthy and infested conditions. Interspecific differences in resistance to pest infestation were assessed based on trait and spectral susceptibility. The results showed that photosynthetic pigments and anthocyanin correlated significantly with the health status of mangrove species. Chlorophyll a, chlorophyll b, and total chlorophyll contents in native species decreased significantly after infestation compared to those in exotic species, which led to consequent decreases in red-edge range reflectivity. Our findings demonstrate that both exotic species, Sonneratia apetala, and Sonneratia caseolaris, have much higher resistance to pest infestation than native species.