Interaction between feeding efficiency and digestive physiology of Plodia interpunctella Hubner (Lepidoptera: Pyralidae) on different date fruit varieties

Abstract

Dates are one of the products that are attacked at postharvest by some insect pests' in packinghouses or storages. Plodia interpunctella Hubner (Lepidoptera: Pyralidae) has become one of the major date fruits pests during the post-harvest storage, causing signi cant losses. In this study, the nutritional performances and digestive enzyme activities of P. interpunctella larvae fed on different date fruits including Dayri, Estemaran, Fersi, Halavi and Zahedi varieties were evaluated. Moreover, date fruits were analyzed to determine their secondary metabolites contents, including phenols, avonoids, and antioxidant activity. The results indicated that the highest relative growth rate (RGR) and relative consumption rate (RCR) were obtained in the P. interpunctella larvae fed on Zahedi variety. In contrast, the lowest RGR and RCR values was observed in the larvae fed on Estemaran and Fersi varieties, indicating the lower tness of these host plants for larval development. According to our ndings, the highest larval, frass, pupal weight and consumed food was related to the larvae fed on Zahedi variety. The results also showed that the lowest level of amylolytic and proteolytic activity was reported on P. interpunctella larvae fed on Estemaran variety. Furthermore, the protein content was the lowest in the larvae fed on Estemaran variety, while the lowest level of glycogen content was found on the larvae fed on Dayri variety. The lowest total phenolic content was signi cantly reported in Dayri variety, which con rms the suitability of this variety for feeding and development of larvae.