Routes to novel pesticides: production of alkaloid defensive chemicals in biocontrol ladybird species

Ladybirds are economically important biocontrol agents, used to control aphids, scale insects and other species of crop pests. The bright, contrasting colours of these insects are designated warning colours, as they indicate to predators that the ladybirds contain distasteful or toxic alkaloid compounds. Different ladybird species contain different mixtures of alkaloids. Research has demonstrated that extracts prepared from Harmonia axyridis and (-)-adaline, an alkaloid from A. bipunctata, are potent inhibitors of acetylcholine induced whole-cell currents in human muscle cells and locust neurons. Further, there appears to be distinct and specific selectivity in the activities of ladybird alkaloids, providing an exciting source of agents which have the potential to form novel insecticides. This project seeks to characterise the pathways involved in the synthesis of alkaloids. Genes involved will be identified from the genome and transcriptome of A. bipunctata. Functional analysis and investigation of corresponding pathways in additional ladybird species will provide insight into the targets and potential uses of the compounds in crop pest control.