Finding eggs on pipevine plants is exciting. For most of the United States, it is easy to know which laid the eggs, Polydamas (Gold Rim) Swallowtail or Pipevine Swallowtail. For the states where both species are found, confusion can reign.
It is simple to tell the difference. Pipevine Swallowtail eggs are burgundy red. Polydamas (Gold Rim) eggs are yellow.
Although female butterflies usually lay eggs on the correct species of pipevine, sometimes they make mistakes. Here is a partial list of which pipevine species are a host for which butterfly species.