Subject: What caterpillar
Geographic location of the bug: Hong Kong
Date: 04/15/2018
Time: 11:52 PM EDT
Your letter to the bugman: Hi there! We found these caterpillars on a lime plant we were growing in school. It is springtime in Hong Kong. There are many plants and trees in our playground, but there are no other lime plants here. The lime plant was a growing project, And isn’t normally in the playground so I wonder if this is actually their usual food. Do you know what species these caterpillars are and what do they eat? Thank you
How you want your letter signed: From Maddie
Dear Maddie,
When caterpillars are found on a plant, one can with some assurance deduce that the caterpillar is feeding on that plant. Butterflies and moths will lay eggs on plants that are suitable food sources for their caterpillars and that is what happened to your lime tree. There are several species of Swallowtail Butterflies with similar looking caterpillars that feed on lime and other citrus tree leaves. We believe your caterpillars are those of a Common Mormon, Papilio polytes, and according to Butterflies of Singapore: “The local host plants include the Indian Curry Leaf plant and various Citrus spp. One notable addition is the Mangrove Lime (Merope angulata) which was found to be utilized as larval host plant by members of the Plant Systematics group of the Department of Biological Sciences (NUS) in the recent past.” The site also has nice images of the caterpillars and they look like your individuals. We would not rule out that these might be the caterpillars of a Lime Swallowtail, Papilio demoleus, which is also pictured on the Butterflies of Singapore site.