Dead fly. Coloured scanning electron micrograph (SEM) of an unidentified fly (order Diptera) that has been killed by impact with a car headlamp. Examination of dead insects collected from cars have provided evidence during forensic investigations of crime scenes, a field known as forensic entomology. Recent insect population surveys have involved drivers counting the number of dead insects found on their licence plates. It is thought that in recent years, insect numbers have declined owing to changes in agricultural practices. Lower insect numbers affect birds and other wildlife that rely on insects for food. Magnification unknown.