Scientists have built a family tree to map the journey of insects on this planet Bug-bear: To most of us insects are a pest; but to a group of about 100 researchers, they may contain the key to humans and our environment. Next time you consider exterminating the silverfish clan eating your precious books, know you'll be killing a living fossil. The first insects appeared on Earth around 479 million years ago and were probably a close relative of the wingless silverfish. For those who hear the word insect and immediately reach for a spray can, news that scientists have mapped the origin of a bug's life may make your skin crawl. "Those little insects that live in your cupboard and look a bit like a funny walking fish, they've been around nearly 500 million years," says the director of the Australian National Insect Collection at CSIRO, David Yeates. Dr Yeates is one of about 100 international researchers who have built the world's first extended family tree for insects - a diverse group that contains one in every two animals on the planet. Insects are essential to human health and the environment, recycling plant and animal material into nutrients and pollinating food crops, worth billions of dollars each year. But insects also spread diseases, and greater insight into their evolution will help researchers explore possible treatments for deadly infections such as malaria. The research team have also pinpointed the time insects took to the air: around 405 million years ago. Dr Yeates said the first winged bugs were probably a variety of primitive dragonfly, whose facility for flight evolved about the same time plants started to grow tall. "Insects were able to crawl up onto plants and probably began their quest to fly by jumping, then gliding and gradually evolving the flapping wings we see today," he said. Obviously they did this so they didn't have to crawl everywhere, they could escape predators and get to new food. Next, insects evolved sucking mouth parts to feed on plants. Then some species began to metamorphose from squashy larva to pupa to adult, as seen in moths and butterflies today. "These are some of the main ways we think insects have been able to become so successful," Dr Yeates said. The group devised the insect's evolutionary road map using large genetic data sets, integrated with fossil evidence, so they could reconstruct relationships between species far back in time. The project required experts in molecular biology, insect morphology, computing, palaeontology and insect taxonomy, and depended on super-powered computers to crunch through the data sets. "It's like having a small telescope to look at the moon, but you need a giant square-kilometre array to look at the edge of the universe," said Dr Yeates. We've got this giant data set to help us delve back in time and look at these relationships. The insect tree of life has been published in the journal Science.