After dividing up the into three categories based on their diet -- some insects bore through wood while others chew or slurp sap -- researchers chose the most damaging species from each category. Then they analysed the cost of these “poster pests” to five sectors: federal and local governments, households, residential property values and timber values. The non-native bugs cost local governments a whopping 1.7 billion dollars every year, while also gobbling up 830 million dollars in residential property values.