The receptor that the Swallowtail butterfly uses to detect leaf chemicals when choosing a suitable host plant for its eggs is identified in a study published in Nature Communications this week. This shows how the butterfly can correctly identify the small number of host plants it will lay eggs on.
The Swallowtail butterfly, Papilio xuthus, is known to only lay eggs on certain plants. In order to identify these plants, the butterfly drums on the surface of leaves to release leaf chemicals. Using artificial leaves soaked with compounds made from host plant leaves, Katsuhisa Ozaki and colleagues show that the butterfly uses the PxutGr1 receptor to detect synephrine in these leaf chemicals when selecting a host plant.