Effect of prior diet exposure on feeding preference and host selection in Spodoptera litura and Spodoptera frugiperda: A comparative study

Abstract

Polyphagous insects feeding behaviour are influenced by chemical cues of host plant, nutritional value and experience to prior feeding. Understanding how larval diet affects host preference is important for studying plant–insect interactions and pest management strategies. In this study, both Spodoptera litura and Spodoptera frugiperda feeding preferences were explored using dual-choice assays. Both species were reared on leaves of Ricinus communis under laboratory conditions to check whether feeding on a common diet influences subsequent host selection. Larvae were used in the dual choice assays from third instar. The feeding responses were recorded as the larva took first bite on a food source. Results showed that both species of larvae fed on all types of diets showing polyphagous nature. However, the feeding response on artificial diet was higher compared to natural plant diets in both the species. In plant-based comparisons, castor leaves were selected more than cabbage leaves. This study suggest that prior diet exposure, nutritional quality and plant chemical cues may influence the feeding behaviour of larvae. During the dual-choice assays, volatiles emitted from larvae during feeding as well as non-feeding conditions were collected for further analysis using electrophysiological techniques.