Effect of elevated CO2 and temperature on biochemistry of groundnut and inturn its effect on development of leaf eating caterpillar, Spodoptera litura fabricius

Climate change in terms of elevated CO2 (eCO2) and temperature may have host mediated effects which could affect the survival, growth and development, and population dynamics of insect herbivores. The present study aimed to examine the growth and development of leaf feeding Spodoptera litura (Fabricius) (Noctuidae: Lepidoptera) reared on groundnut (Arachis hypogaea L.) grown under different climate change treatments under open top chambers (OTC’s) at University of Agricultural Sciences, Raichur, Karnataka. Significantly lower leaf nitrogen, higher carbon, C: N ratio, phenols and tannins was observed in the groundnut foliage grown under eCO2 conditions. This alteration in food quality in elevated conditions significantly affected the growth parameters of S. litura in the form of increased food consumption, increased larval weight and more faecal matter production due to extended larval and pupal duration. This resulted in reduced fecundity, particularly in the population raised under eCO2 conditions compared to ambient conditions. Further, the insect larva showed increased approximate digestibility and relative consumption rate under eCO2 condition coupled with reduced efficiency of conversion of ingested food. As a result, the relative growth rate was decreased under eCO2 conditions. In nutshell, it can be concluded that eCO2 concentrations altered the quality of groundnut foliage as it was noticed by the changes in biochemical constituents of the foliage and has the negative effect on the growth and development of S. litura.