Giant Swallowtail Butterflies and Your Citrus Trees

It wasn't until I had watered the last of the citrus trees that I realized the bird droppings were some kind of larvae. That was the beginning of my pursuit of the Giant Swallowtail Butterfly.


The Giant Swallowtail Butterfly, Heraclides cresphontes is the largest butterfly in the United States and Canada with a wing span reaching between 4 inches to over six inches.


These are beautiful graceful butterflies. As they glide along, they're usually high enough to make it difficult to get a good picture. I finally found this one visiting the zinnias.


The butterflies are known to seek out nectar from azalea, bougainvilla, bouncing Bet, dame's rocket, goldenrod, Japanese honeysuckle, lantana, and swamp milkweed.

Caterpillar hosts are trees and herbs of the citrus (Rutaceae) family; also prickly ash, Zanthoxylum americanum, common rue, Ruta graveolens, and hop tree, Ptelea trifoliata. On the left you'll see a mature caterpillar (disguised as a bird dropping). The one on the right is a younger caterpillar.


A couple of the caterpillars made their way up the side of the house where they transformed into their chrysalis state.


The female butterflies lay single eggs on the leaves and twigs of the host plant.


As I watched the larvae munching on the citrus trees, it became clear to me that they were not harming the trees at all, and the trees hosting the most larvae began sprouting new young shoots and leaves; they also did not affect the fruit flowering or fruits forming on the trees.