Temperature-Driven Variations in Fitness and Physiological Responses of Aphis craccivora Koch and Aphis gossypii Glover (Hemiptera: Aphididae) on Lablab purpureus subsp. Bengalensis (Jacq.) Verdc

Abstract

Temperature, an important abiotic factor, alters physiological processes in insects. This study includes effect of temperatures under laboratory (7°C, 12°C, 17°C, 22°C, 27°C and 32°C) and field (10°C–26°C) conditions on the life table parameters, total reactive oxygen species (ROS), hydrogen peroxide (H₂O₂), malondialdehyde (MDA) content and activities of antioxidative [superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX)], detoxifying [acetylcholinesterase (AChE), β-glucosidase and glutathione-S-transferase (GST)] and oxidoreductive [peroxidase (POD) and polyphenol oxidase (PPO)] enzymes of Aphis craccivora Koch and A. gossypii Glover (Hemiptera: Aphididae) on Lablab purpureus subsp. bengalensis (Jacq.) Verdc. plants. The longevity and fecundity of both aphids were highest at 22°C, and A. craccivora showed similarity between 22°C and field condition but A. gossypii showed similarity between 17°C and field condition, suggesting that A. craccivora is able to withstand more fluctuating temperature stress than A. gossypii. Total ROS, H₂O₂ and MDA content were increased at low (7°C) or high (32°C) temperature but these parameters were more increased at high temperature than low temperature, suggesting that high-temperature stress is more harmful for both aphids. Under low (7°C) or high (32°C) temperature stress, the levels of antioxidative, detoxifying and oxidoreductive enzymes were increased in both adult aphids compared to 22°C or field condition, implicating that both these aphids are trying to detoxify excess ROS by producing more antioxidative, detoxifying and oxidoreductive enzymes. The mortality of both aphids was higher at low (7°C) and high (32°C) temperatures, implicating that both aphids could not detoxify excess ROS by the coordinated action of antioxidative, detoxifying and oxidoreductive enzymes. The findings of this study can assist to envisage the population dynamics of these two important aphids, which can assist in management of these two sucking insect pests in the crop field.