Giant Swallowtail Butterfly
Giant Swallowtail Butterfly (Photo Rebecca Jordi)

University of Florida/IFAS Extension Director for Nassau County, Rebecca Jordi, provides expertise and tips about northeast Florida gardening and landscaping.

Garden Talk

QUESTION:   What is this caterpillar?  LN  

JORDI: This is the time of the year when caterpillars will be showing up in our plants and feasting on the leaves.  This is one caterpillar I do not mind finding on my citrus trees.

You and I talked about how concerned you were to have the caterpillars feeding on your young citrus trees, but I assure you, the trees will not die and there will still be plenty of leaves for the tree to produce fruit.

The caterpillar is the orange citrus caterpillar.  It is important to provide larval food sources for our pollinators. The orangedog caterpillar, Papilio cresphontes, develops into the giant swallowtail butterfly. This butterfly can be found from Canada to the Rocky Mountains to Center and South America.

The larvae initially look like a bird dropping. Once it becomes larger it may mimic a snake and if disturbed can put out an osmeterium which is a defensive organ. On the orangedog, they resemble the forked tongue of a snake. They are even red – very threatening. When the orangedog pupates, it attaches a small silk thread to a stem and angles its body at a 45-degree angle. There may be 2-3 generations a year.

The orangedog caterpillar will feed on a few other plants such as Hercules club or hoptree.  To show you how unconcerned I am with this caterpillar, I placed it on one of the citrus trees in the UF/IFAS fruit demonstration garden in Yulee. For more complete information on this native butterfly, read “Giant Swallowtail, Orangedog, Papillo cresphontes by H.J. McAuslane.  

QUESTION:   What is this caterpillar? RJ

Underwing Moth Cocoon
Underwing Moth Cocoon (Photo Rebecca Jordi)

JORDI:   I let the caterpillar you brought in pupate in my office and found out it was an underwing moth in the genus Catocala.  Underwing moths produce large caterpillars and the moths have colorful hindwings. The average size of the moth’s wingspan is between 1.5 to almost 3 inches.

After building the cocoon, the underwing caterpillar took about 1 week to develop into an adult moth. The forewing is speckled making easy to hide against the tree trunk as it looks like tree bark. Adults can be found resting on the tree trunk during the day. Depending on the species, the hindwing will have brightly colored bands in red, pink, orange or yellow with black bands on either side of the color band.

Underwing Moth Adult
Adult Underwing Moth (Photo Rebecca Jordi)

They can be found throughout North America. The underwing moth’s habitat is most often in deciduous forests. Like most moths, they are active at night around lights at businesses. The larvae feed on large tree leaves. They do not do enough damage to the trees to warrant any chemical application.

Those of you who know me, know I have a large collection of insects in acrylic, so I can show them to children and adults.  I did not have the heart to kill this moth since I had “raised” in my office.  I released it around an oak tree.  See, I’m not totally heartless. __________


Rebecca L. Jordi
Nassau County Extension Director
UF/IFAS Environmental Horticulture 
543350 U.S. Highway #1
Callahan, FL 32011
904-530-6351