You might have seen them in a hotel. You might have read about them in the news. Maybe you’ve seen them star in social media videos filmed on the London underground. But should we really be worried about bed bugs?   The little critters evolved from feeding on bats and birds to humans thousands of years ago and were part of society for hundreds of years. But with the invention of synthetic pesticides, bed bug populations declined significantly after the Second World War. However, as pesticide resistance grows and the world becomes increasingly connected, bed bugs are making a resurgence.   Entomologist Liam Crowley, from the Department of Biology, tells us what to look out for and how to keep them at bay in our latest podcast. But don’t worry, they’re not as common as you might think!