Migratory animals are no stranger to our neck of the woods. Every year, Florida is host to countless creatures as they make their way from one place to another in search of food, nesting sites, or just a change of scene. From hummingbirds to manatees, it can be interesting to watch the annual cycle of nomadic animals.
A gulf frittilary butterfly.
One of the smaller wayfarers we see year-round, but especially when they migrate south in the fall, is the gulf frittilary butterfly, Agraulis vanillae Linnaeus. They spend the warmer months of the year in the southeastern United States, following frost-free weather as temperatures drop. During the winter, they enjoy the sunshine of peninsular Florida.
The gulf frittilary is a medium-sized butterfly, with a wingspan of 2½–3½ inches. Females are larger than males. It is bright orange in color, with black markings on the top of its wings and silvery-white spots on the bottoms. In its larval form, it is also bright orange in color, with dangerous-looking spines along the length of the caterpillar. Despite their appearance, these do not sting.
The gulf frittilary caterpillar looks dangerous, but won’t sting. Please do not eat it, however.
If given a choice its larvae will feed primarily on passionflower (Passiflora incarnataand related species), but have also been seen snacking on buttonsage. Toxins from passionflower concentrate in the larvae and butterflies, making them poisonous to predators – much like the monarch butterfly and its host plant, milkweed. The insect’s bright coloration serves as a warning that it is not to be eaten.
Keep an eye out for these beautiful butterflies and consider planting a passion vine in your landscape to help them out. The caterpillars may eat the leaves, but in giving them a feast you’ll help them grow into adult butterflies. Once they do mature, they are fantastic at pollinating many of our native wildflowers, further beautifying the world around them.
For more information see the University of Florida’s article here.
Throughout the year, people with citrus trees of any sort may notice some damage to the leaves. Chewing damage, which leaves pieces of the leaf missing, is a common sight. The likely culprit for this type of damage is an insect that is very common in our area, but seems to have multiple personalities!
The adult form of this peculiar creature is the giant swallowtail butterfly, Papilio cresphontes Cramer. A large black-and-yellow butterfly, it is found throughout the country east of the Rocky Mountains, and is present in north Florida most months of the year. Adults spend their days as many other butterflies do, flitting from flower to flower in search of nectar. They are attracted to a wide variety of blossoms, pollinating as they go.
The giant swallowtail butterfly. Photo courtesy of Donald Hall, University of Florida
Females lay tiny round eggs individually on the surface of plant leaves. Though their larvae may eat numerous types of leaves, one of their favorites seems to be those of citrus trees. This means that though the adults may be considered beneficial as pollinators, their caterpillars are often thought of as pests.
Bird poop or caterpillar? The orange dog caterpillar is, in fact, a caterpillar.
Similarly, the beauty of the adult butterfly is quite different than the appearance of their younger selves. The caterpillar of the giant swallowtail, often called the ‘orange dog’ caterpillar, relies on camouflage to keep itself safe. Even with this it displays multiple personalities, so to speak. Larvae of any age may be mistaken as bird droppings on a leaf. Their irregular patches of white and brown make them look like the leavings of a passing avian, which predators are probably likely to pass over. Older caterpillars have another trick up their sleeve, with markings on their head that mimic the head of a snake. Disturb one enough and it may even flash a forked, bright orange protuberance called the osmeterium, which may resemble the tongue of a snake. This gland also emits a musky odor to make the insect even less attractive to potential predators.
Snake or caterpillar? The osmeterium might look like a snake’s tongue, but don’t be fooled. Photo courtesy of Donald Hall, University of Florida
Whether wearing a beautiful, ugly, or scary face, these insects are here to stay. Thankfully, they don’t often do enough damage to citrus trees for homeowners to worry about. Young trees in danger of being defoliated may need some protection, but an established tree can lose a leaf or three with no issues.
If control is called for, hand-picking the caterpillars is a viable option, as long as the tree is small enough to reach the branches. A product called Bt, short for Bacillus thuringiensis, is another option. Applied to the leaves, this insecticide only affects caterpillars, and shouldn’t harm other pollinators.
October is an important month for butterflies. The monarchs are making their epic migration towards Mexico, gracing us with their presence as they stop to feed on saltbush or lantana plants along the coast. But our homegrown orange-and-black butterfly is showing up everywhere right now, too. The Gulf fritillary (Agrautis vanillae) is a smaller species, but also features bright orange wings with black stripes and spots. Their caterpillars come dressed for Halloween, too—they are a deep orange color with black legs and spikes. While the caterpillar is not venomous to any potential predators, the spikes are quite intimidating and serve a protective function.
A gulf fritillary butterfly gathering nectar from a similarly brilliant orange flower. Photo credit: Carrie Stevenson, UF IFAS Extension
Fritillary (name from the Latin “chessboard”) eggs are bright yellow and laid primarily on varieties of passionflower vines, which the caterpillars feed voraciously upon. Passion vine is an important host plant for the zebra longwing as well, which is Florida’s state butterfly.
Gulf fritillaries are found in all 67 Florida counties, and may live throughout the southeastern United States, Mexico, and central and south America. They are found in varied habitats but prefer open, sunny spots in fields, forests, and gardens. The butterfly’s wing shape puts them into the “longwing” category, as their elongated wings spread wider than other species.
Caterpillar of the Gulf fritillary butterfly on corkystem passionflower. Photo credit: Jaret C. Daniels, University of Florida.
In the fall, fritillaries migrate to the warmest ends of their range. By spring, they move slightly north into North Carolina or interior Alabama.
A number of landowners in our region have been noticing a number of caterpillars coming down from the treetops. Sometimes appearing in vast numbers, the forest tent caterpillar has been found throughout Florida and the United States. Several years of heavy infestation occurred in Central Florida more than a decade ago, but populations are usually not high enough to cause significant damage to trees.
A forest tent caterpillar. – Photo courtesy of Shoal Sanctuary Nature Preserve.
The forest tent caterpillar is the larval stage of a somewhat nondescript brown moth. The moths lay their egg masses on twigs, and the eggs hatch in the spring. Caterpillars feed on a variety of tree species, but seem to prefer oak and gum trees. They spend anywhere from two to six weeks eating. When they are nearing maturity, they can become a problem for humans who do not appreciate the many droppings they produce, or their habit of descending from the trees to find places to spin their cocoons. They are sometimes attracted to lights or the walls of buildings, where they congregate in search of a place to pupate. They are not harmful to people, however.
A forest tent caterpillar egg mass. – Photo courtesy of Jeffrey Lotz, Division of Plant Industry
Particularly cold winters may help decrease populations of these caterpillars. Inclement weather or high temperatures may do the same in the summer, and natural predators often help to control populations when present as well. Controlling forest tent caterpillars is most often unnecessary even when there are large numbers of them. It may help to avoid parking cars under large infestations or to turn off outdoor lighting that might attract them at night. If they wander indoors, check screens and window seals to be sure there are no gaps for them to enter.
If these or other caterpillars become such a nuisance that control measures must be considered, consider using a product such as Bacillus thuringiensis, or Bt, which specifically affects caterpillars and not other beneficial insects. Keep affected trees healthy with proper fertilization and watering, and even a defoliated tree will probably recover from any damage these insects cause. For more information, see our EDIS publication on the Forest Tent Caterpillar or contact your local Extension office.
If you’ve been raking leaves recently, you’ve probably noticed little green worms hanging from the trees. They seem to be in abundance this year and can be found crawling on driveways, just hanging around, and maybe even feeding on oak tree leaves.
These green worms that are all over the yard are oak leafrollers (Archips semiferanus) or oak leaftiers (Croesia semipurpurana). Some people may refer to them as inchworms, however a number of different caterpillars can go by that name. Leafrollers and leaftiers range in length from 1/4″ to 1″. The adult form of these insects is a 1/2″ long moth. The oak leafroller moth is mottled tan and brown and the oak leaftier moth is yellow with brown markings.
An oak leafroller caterpillar crawling on a leaf. Photo Credit: Blair Fannin, Texas A&M University
In May, the adults of both species lay their eggs in the twigs and leaf buds of a number of tree species. The eggs don’t hatch until March of the following year. When the caterpillars emerge, they feed on the newly forming leaves and flowers of oak, hackberry, pecan and walnut trees. If they are disturbed, they will stop feeding and hang from a strand of silk. Oak leafroller caterpillars pupate in tree branches, while oak leaftier caterpillars drop to the ground and pupate in leaf litter. Adult moths emerge in one to two weeks.
A leafroller moth with wings spread. Photo Credit: U.S. National Museum
The oak leafrollers and oak leaftiers don’t really do enough damage to be considered pests, but they are a bit of a nuisance. Thankfully, birds and parasitic wasps will eat and kill the majority of the population. For in-depth information on most of the interesting insects in your yard, please visit the UF/IFAS Featured Creatures Website.
