What we do is we put a monarch in a big cage, a medicinal plant on one side, a non-medicinal plant on the other side, and then we measure the number of eggs that the monarchs lay on each plant.
我们把帝王斑蝶放进大笼子里， 一边的乳草是有药性的，一边没有， 然后测量它们在两种乳草上的产卵数，