writes "Entomologists have never been able to identify flying insects automatically. But not through lack of trying. The obvious approach is to listen out for the frequency of the wing beat. But acoustic microphones aren't up to the job because sound intensity drops with the square of the distance, so flying insects quickly drop out of range. Now a group of researchers has solved this problem using a laser beam pointing at a photosensitive array. Any insect flying through the beam, casts a shadow of its beating wings that can easily be recorded at distances of several metres. Using this new device, the team has created a dataset of millions of wing beat recordings, more than all previous recordings put together. And they've used the dataset to train a Bayesian classifier algorithm to identify flying insects automatically for the first time. That opens the prospect of a new generation of bug zappers that kill only certain insects or just females rather than males. That could have a big impact on human health since mosquitoes and other flying insects kill millions of people each year. It could also help in agriculture where insects threaten billions of dollars worth of crops."