The answer to your question, Christi, is no. Popillia japonica, the Japanese beetle, is not known to be toxic to pets. However, these iridescent pests do have very hard exoskeletons, and physical irritation to the gastrointestinal tract can occur in addition to general stomach upset from ingesting the insect. The bottom line? While eating a Japanese beetle might make your Westie vomit, you need not be concerned about him becoming poisoned as a result.