Impact of temperature stress on demographic traits and population projection of Bactrocera dorsalis

Abstract

Climate change generally influences all the living world, including insects, so all organisms cope with these stresses to survive. Temperature rise leads to increased insect pest severity, while cold acclimation helps insects to survive in temperate areas in several complex ways. The Oriental fruit fly, Bactrocera dorsalis, is one of the most economically important invasive pests of fruits and vegetables worldwide. In this study, we investigated the effect of low (LT: 3 degrees C) and high (HT: 38 degrees C) temperature stress on key biological and population parameters of B. dorsalis using an age-stage, two-sex life table approach. The results showed that the mean developmental duration of the larval stage was significantly prolonged in both HT (6.82 d) and LT (7.80 d) compared to the untreated group (6.33 d). The developmental duration of pre-adult stage was substantially increased when treated with LT (19.57 d) and HT (18.03 d) as compared to control insects (17.51 d). Compared to the control, the mean longevity of male and female flies was significantly prolonged in both LT and HT treatments. The adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), and oviposition days of B. dorsalis were increased under both temperature stress conditions. The number of eggs per female was also significantly higher in LT (869.70 eggs) and HT treatments (846.90 eggs) compared to control (684.56 eggs). Furthermore, the total population size of B. dorsalis was highest in HT treatment followed by LT compared to control after 100 d. This study reveals that temperature stresses at larval stage increased the reproduction, development, and life span of B. dorsalis, these altered biological traits during the heatwave and cold conditions could have significant agricultural impacts.