Response of Aphis craccivora Koch to elevated CO2 on Cowpea

Abstract

Changes in climate and weather could profoundly affect the population dynamics and status of insect pests of crops. Aphids are ubiquitous insect herbivores whose behavior could be influenced by climate change. We studied the impact of elevated CO2 (eCO2) on Aphis craccivora Koch on cowpea (Vigna unguiculata L.). Cowpea plants were grown under ambient (380 ppm) and elevated (550 and 700 ppm) CO2 conditions in open top chambers (OTCs). Feeding trials were conducted using ‘cut leaf’ technique and the aphids were cultured individually in the laboratory. Results showed that the host plant and aphid species were significantly and positively influenced by eCO2. The mean fecundity (number of nymphs per day, 80%), Mean relative growth rate (MRGR, 8%) and adult weight (22%) of aphids increased but the longevity (5 %) and development time (5%) decreased significantly at eCO2 conditions over ambient CO2. Bio chemical analysis of cowpea foliage indicated an increased C:N ratio (8%) and decreased nitrogen content (7%) and non-significant variation of carbon and phenol content at eCO2 conditions