When was the last time you were stung by a wasp? Or followed by a cloud of midges? Or saw a butterfly? All these normal occurrences are becoming rarer. Insect numbers are in serious decline – in some places by over 90%. Yet we rely on insect pollination for most of our agriculture, they are a prime food source for birds and fish, and they are a key support for life on Earth. Oliver Milman, environment reporter for Guardian US, investigates the reasons for their disappearance, with views from scientists and entomologists studying this catastrophe. Celebrating the incredible variety of insects, he highlights the need to wake up to this impending environmental disaster. In conversation with writer and editor Kitty Corrigan.