Changes in the Physiological Adaptation and Regulation Ability in Harmonia axyridis under Chlorpyrifos and Imidacloprid Stress

Abstract

As the dominant natural enemy of aphids, Harmonia axyridis plays a crucial role in integrated pest control (IPM) in agro-ecosystems. In order to study the physiological adaptation and regulation ability of Harmonia axyridis to insecticides under chemical pesticide stress, ladybirds were treated with organophosphorus chlorpyrifos (chlorpyrifos) and new nicotine imidacloprid (imidacloprid) to explore the physiological adaptability of ladybirds under chemical pesticide stress by activating trehalose metabolism. The results showed that the imidacloprid affect the larvae develop to pupate, resulted in the H. axyridis died and significantly increased the food consumption of Harmonia axyridis, while the chlorpyrifos prolong the development period of pupae significantly and decreased significantly the food intake of H. axyridis fed with aphids treated with chlorpyrifos. It was further found that Chlorpyrifos could inhibit the activity of the trehalase, while the trehalase activity increased under imidacloprid stress, but both insecticides could decrease the trehalose content. The TRE and TPS genes of Harmonia axyridis under chlorpyrifos and imidacloprid stress were upregulated or downregulated. These relevant results can provide a strong reference for the rational use of chemical pesticides or biological pesticides to control pests in the future.