I’ve noticed giant swallowtail butterflies (Papilio cresphontes) a little early this year. The giant swallowtail is one of the largest and most beautiful butterflies in our area. Its larval stage or caterpillar is known as the orange dog. This unusual name comes from the fact that it feeds on the young foliage of citrus trees.
The orange dog caterpillar is mostly brown with some white blotches, resembling bird droppings more than a caterpillar. When disturbed, it will try to scare you off by extruding two orange horns. It doesn’t sting or burn but contains a pungent odor. When touched it may leave your hand or fingers with a strong smell that is hard to wash off.
I’ve had some minor feeding on citrus trees in my landscape from orange dog caterpillars. But I tolerate them. I’m not growing the citrus to sell. Sure, the caterpillars eat a few leaves but my citrus trees have thousands of leaves. New leaves eventually replace the eaten ones. I leave the caterpillars alone. They eat a few leaves, develop into chrysalises and then emerge as beautiful giant swallowtail butterflies. The whole experience is a great life lesson for my two children. And, we get to enjoy beautiful giant swallowtail butterflies flying around in our landscape and still get plenty of fruit from the citrus trees. It is a win, win, win.
In some cases, the caterpillars can cause widespread defoliation of citrus. A few orange dog caterpillars can defoliate small, potted citrus trees. Where you cannot tolerate their feeding habits, remove them from the plant. But consider relocating the caterpillars to another area. In addition to citrus, the orange dog caterpillars will use the herb fennel (Foeniculum vulgare) and rue (Ruta graveolens) as a food source. Some butterfly gardens plant citrus trees to provide food for orange dog caterpillars to turn into the giant swallowtail butterflies. So you could plan ahead and grow some fennel, rue or find a butterfly garden in your area for the purpose of relocating the larvae.
The adult butterflies feed on nectar from many flowers, including azalea, bougainvillea, Japanese honeysuckle, goldenrod, dame’s rocket, bouncing Bet, and swamp milkweed. Some plants in this list might be invasive.
Keep in mind that mature citrus trees can easily withstand the loss of a few leaves. If you find and allow a few orange dog caterpillars to feed on a few leaves of a mature citrus tree in your landscape, you and your neighbors might get to enjoy the spectacular giant swallowtail butterfly.
More information on the giant swallowtail butterfly is available through online at http://edis.ifas.ufl.edu/in134.