The Database of Insects and their Food Plants (DBIF for short) is a fantastic resource for wildlife gardeners.
It shows the known associations between plants and insects, ie which bugs are eating your plants! Use native plants in your garden where possible, as they provide a food source for insects, which are then eaten by other wildlife.
A prolific example of why you should grow native plants is the English or Pendulate Oak (Quercus robur), which not only supports a whole range of insects that eat it, but also provides habitat, food and protection for a range of animals (including us!).