LAUSR

BACKGROUND Global climate change, will result in an increasingly arid weather which will impose a significant impact on agriculture. The occurrence dynamics of plants, phytophagous insects and their natural enemies under drought have attracted much attention. The consequences could be useful for controlling insect herbivores. Leptinotarsa decemlineata (Say) is one of the most important potato pests, which causes serious damage to potato production. Arma chinensis (Fallou) is a parasitoid of L. decemlineata. However, how drought will affect the titrophic interactions among potato and these insects are unknown. RESULTS In this experiment, L. decemlineata and A. chinensis were subsequently released on potato plants, under water stress treatments. Thereafter, plant height, stem diameter and yield of potato, the growth and reproduction of L. decemlineata, and the longevity of A. chinensis adults were periodically recorded. The results showed that drought had crucial effects on height, stem diameter and yield of potato (P<0.05); it also exerted a significant impact on the pre-oviposition period, oviposition days, fecundity and life table parameters of L. decemlineata (P<0.05). Moreover, drought significantly reduced the longevity (P<0.05) and the survival rate of A. chinensis adults. The longevity of adult A. chinensis was only 29.00±3.00 d and the harvest rate of L. decemlineata adults was only 1.42±0.07% under drought treatment. CONCLUSION In this experiment, we evaluated the bottom-up effects of drought on tritrophic interactions involving potato, L. decemlineata and A. chinensis, and discuss the implications of the findings for the integrated pest management programs involving the pest. Future promising research directions are then proposed.