Host Defensive Responses and Nutritional Ecology of Six Insect Pests on Sesame

Host plant defensive responses towards herbivory were derived from a long run-in evolutionary arm race and their phenotypic plasticity increase fitness against the herbivores. Six insect pests (Diacrisia casignetum, Spilosoma obliqua, Spodoptera litura, Spilarctia lutea, Helicoverpa armigera and Plutella xylostella) were reared on respective herbivore damaged plants (HDP), mechanically damaged plants (MDP) and intact plants (IP) of sesame (Sesamum indicum, cv. Rama) during 2021–2023. The nutritional ecology and population growth of the selected pest species were significantly (F5.12 = 9.451; P < 0.001 and F5.12 = 3.404–123.653; P ≤ 0.038, respectively) affected by the host defensive response in terms of their respective chemical regime with significant (F7.16 ≥ 6.373; P < 0.001) variations. The chemical profile of sesame was changed in the order of HDP (P. xylostella > S. obliqua > H. armigera > S. lutea > S. litura > D. casignetum) > MDP > IP. The Pf were in almost in same pattern (H. armigera > D. casignetum > S. obliqua > P. xylostella > S. litura > S. lutea) on the three conditions (HDP < MDP < IP) as in GRR or mx. The overall population growth displayed different patterns of significance (F5.12 ≥ 4.215; P ≤ 0.019) and were in the same order (HDP < MDP < IP) as in nutritional ecology due to different biotic potential of the pests as well as herbivore specific host defensive responses. The findings inform about the specific elevation of both PMs and SMs in respective HDPs of sesame from MDPs and IPs and their impact on ecology of the insects and that can be useful to exploit the pests as a part of integrated pest management (IPM) in near future.