University of Florida students aren’t just finding relief from the heat under shady oak trees across campus this spring. They’re finding caterpillars.
Many Gainesville residents are used to the fuzzy green visitors and even expect their yearly return. But now that the caterpillars are here, it’s nearly impossible to walk outside without an encounter.
Tussock moth caterpillars are creating a seasonal buzz across the city. While the insects are native to North America, Gainesville’s environment helps them thrive.
Oak trees act as both shelter and buffet. The caterpillars spend this stage of their lives feeding on tender leaves, building up the energy they’ll need to survive in adulthood, a stage during which they won’t eat at all.
Rebecca Baldwin, an entomologist at the University of Florida, said this surge is part of a natural cycle.
“They’re timed to the environment,” Baldwin said. “When the leaves are young and most nutritious, that’s when the caterpillars are going to be most active.”
After feeding, the caterpillars will leave the trees to pupate, often attaching themselves to buildings, benches and other surfaces around campus, another reason students are noticing them more than usual.
After pupating, the caterpillars emerge as moths, often going unnoticed compared to during their more attention-grabbing larval stage. Unlike butterflies, adult tussock moths have short life spans and are focused primarily on reproduction.
In fact, female tussock moths do not have wings and rely on pheromones to attract winged males to reproduce.
Baldwin has lived in Gainesville for more than 20 caterpillar seasons and said she’s heard plenty of student stories.
For many students, encounters with the caterpillars have become part of daily life.
Mathew Maykut, a UF advertising junior, said avoiding them is nearly impossible.
“Every day is something new,” he said. “Sometimes they land on my backpack, once one got in my hair. At this point, I just try not to bother them or crush them. They’re kind of everywhere.”
UF nursing senior Taylor Weinhauer, 19, had a more up-close experience while studying outside Library West when a caterpillar fell onto the inside of her arm.
“They just kind of appeared out of nowhere,” she said. “I didn’t even feel it at first, and then suddenly I had a rash. They really do creep up on you.”
The rash lasted about two days, leaving a light red discoloration on her forearm.
Baldwin said reactions like that can vary from person to person. Areas with more sensitive skin, like the inside of the forearm, are more likely to become irritated.
The caterpillars aren’t poisonous. Instead, the reaction comes from the tiny hair-like spines that cover their bodies. Soft in appearance but sharp on contact, the hairs can lodge in the skin, similar to the way a cactus might.
Akito Kawahara, director and curator of the McGuire Center for Lepidoptera and Biodiversity at the Florida Museum of Natural History, said it’s a common misconception that the caterpillars themselves are dangerous.
“Some people are allergic to certain things, and other people are not. It's kind of the same thing,” Kawahara said.
He also said the yearly panic may be a bit overblown.
“Every year, people think it’s worse than the last,” Kawahara said. “But it’s a very short event.”
As oak trees produce soft, nutrient-rich leaves, caterpillars hatch and begin feeding. Warmer temperatures may be nudging that timing earlier.
According to the Weather On This Day website, climate data shows that temperatures on April 1 have been warming by about 0.4 degrees per decade, a shift that can influence when insects become active.
Kawahara said that doesn’t mean the season lasts longer, just that it may start sooner.
In fact, in a week or two, the caterpillars will be gone.
“They’re walking around looking for a place to pupate,” he said. “But soon you won’t see any of them anymore.”
They may be easy to brush off as a seasonal nuisance, but the caterpillars play a larger role in the ecosystem. The caterpillars are a food source for birds, bats and other wildlife.
He added that there’s another important perspective to keep in mind: The caterpillars were here first.
“These are part of the natural habitat,” Kawahara said. “We’re the ones building around them.”
For now, that means a few extra encounters on sidewalks, on benches and occasionally, on sleeves.
And maybe, in a place like Gainesville, it also means getting used to sharing the shade.