The present invention provides methods for identifying pesticide targets and pesticidal agents using transposable elements in insects and insect cells lines. The invention provides engineered transposable elements for use in identification of pesticide targets. The invention further provides a biological array, a collection of transgenic insect lines or insect cell lines, the genome of each containing at least one transposable element that mutates one of the insect's genes, such that the complete collection contains a mutation in essentially every gene in the insect's genome.