Impact of climate change (elevated CO2 and temperature) on growth and development of cowpea pod borer, Maruca vitrata (Fabricius) (Lepidoptera: Crambidae)

Abstract

Climate change has a widespread influence on agricultural productivity and relies upon the fact that responses vary between crops. Any changes in the nutritional quality of the host plant will have direct influences on associated insect pests and the damage that it causes. In this context, a study was conducted to measure the impact of elevated CO2 and temperature on the growth and development of cowpea (C3 plant) and its herbivore pod borer, Maruca vitrata (Fabricius) under open top chambers at the Center for Agro-climatic Studies, UAS, Raichur, Karnataka. Elevated CO2 had a positive impact on cowpea growth by encouraging crop boom along with vital changes in its phytochemistry. The increased supply of CO2 resulted in higher concentrations of ‘C’ and C-based metabolites and chlorophyll (39.81 µg/cm2) and nitrogen balance index (104.52). However, ‘N’ and N-based compounds were reduced. Larvae fed upon such nutrient-deficient food increased their development period (36.07 ±0.42days) and compensatory feeding inflicting more damage (7.72 webbings/plant). Although the larvae consumed more food, it decreased the body weight of the larvae and pupae, which in turn decreased the percent moth emergence, ultimately decreasing the fecundity (60.09 ± 0.20/female) and fitness of the pest in the long run.

Keywords

• Cowpea
• eCO2 and temperature
• Growth and development
• Maruca vitrata
• phytochemistry