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Mild winter, moist spring good for caterpillars

Les Harrison Special to
the Times
The Apalach Times

The summer of 2020 is off to a good start for Franklin County’s residents. There has been plenty of rain to support the growth of plants and shrubs, but the weeds and insects have enjoyed the moisture too.

Last winter was relatively mild so a minimum of insect eggs were lost. The spring had enough moisture to promote the growth of plants necessary to feed the plethora of these soon-to-be moths and butterflies, among many others.

It is important to understand most caterpillars feed on a specific and narrow range of plants, in some cases only one type of plant. With very few exceptions, they are not the Biblical plague which strips the landscape bare of all plants and trees.

The exceptions, such as armyworm and cutworms, quickly attract the attention of farmers, gardeners, ranchers and flocks of birds which all react accordingly. These multitudes of nascent moths and butterflies are a nuisance because they are attracted to vast quantities of crop monocultures, so they can reproduce quickly.

Fortunately, there are other caterpillars with much better reputations, at least in north Florida. One is the orange dog caterpillar, which can be a problem in Florida’s orange producing region given its exclusive diet of citrus leaves.

As a means of camouflage, the mature caterpillar closely resembles bird droppings, dingy brown and olive green with large white and small purple patches. They also have red osmeterium or horns which they project when threatened, emitting a foul odor.

From this incongruous appearance, this caterpillar transforms into a giant swallowtail butterfly. Its wingspan reaches four inches with a distinctive black and yellow pattern.

The whitemarked tussock caterpillar favors the area’s oak trees. Its four white tufts are carried on its back and offset the black horns and tail. The bright red bulbous head, located just below the black horns, is in stark contrast to the remainder of the body. Their hairs are a noted allergen for any unlucky person who contacts them.

With the start of official summer weeks past, all of these and many more caterpillars are active in Apalachicola’s humid days. Caution is advised because some do produce a sting.

The saddleback caterpillars are mainly green with a brown area at both ends, and a prominent, white-ringed brown dot in the center which resembles a saddle. To add a bit of freakishness to their appearance, they have well-placed defensive spine which can inflict painful stings.

Io moth caterpillar is another of this small group of stinging insects. They are not especially finicky with their diet selections, so they may be encountered on a variety of plants and trees. Their mostly green tubular bodies are easily hidden among the oaks, dogwoods, redbuds and other leafy plants and trees which flourish in Franklin County. Regrettably, they quickly make their presence known if blundered into when enjoying the out-of-doors.

Tiny, needle-sharp spines which cover their body are an excellent deterrent to any bird or animal which considers this caterpillar as a snack option. Each spine is a hollow tube filled with a toxin and topped with a point.

Most caterpillars ultimately morph into butterflies and moths, some which are quite strikingly beautiful. The colorful end products hopefully compensates in some way for the damage done to highly manicured landscapes and vegetable gardens, and the unlucky few who encounter the occasional stinging variety.

To read more stories by Les Harrison, who is a UF/IFAS extension agent emeritus, visit To learn more about caterpillars in Apalachicola and north Florida, contact Erik Lovestrand, the UF/IFAS regional Sea Grant agent in Wakulla, Franklin and Gulf counties, at