Silent and astray, they slip into South Florida homes, a few hundred legs carrying them to a dehydrated doom.
Millipedes, or specifically, the yellow-banded millipedes, are making their presence known in Palm Beach County in a population growth spurt that experts say isn’t well understood.
The millipedes, which feed on decomposing landscape debris, mulch and thatch, are harmless. They aren’t poisonous to animals, don’t bite, and dry up fairly quickly when they wander into air conditioned areas.
But when disturbed, these foreign invaders can give off a foul odor as a defense mechanism. This can happen even when dead.
“We don’t recommend you vacuum them because the odor can get circulated and really stink,” said Bill Schall, a Palm Beach County extension agent with University of Florida’s Institute of Food and Agricultural Sciences, or IFAS. “If you sweep them into a dust pan, or just pick them up, that is better.”
The yellow-banded millipede is not a South Florida native. It is believed to have originated in the Caribbean, and was first found in Monroe County in 2001, according to the University of Florida. It has since spread north to Broward, Miami-Dade and Palm Beach Counties.
Worm-like in appearance and up to four inches long, the yellow-banded millipedes are not insects, but arthropods, meaning they have many body segments. And although the word millipede would lead to the assumption it has 1,000 legs, they are more likely to have several hundred — two pairs of legs on each body segment.
“They’re a nuisance, but not harmful,” said Schall. “In my office we usually see them in the warmer, wetter months, but entomologists don’t totally understand why there are population explosions.”
A UF fact sheet on the yellow-banded millipede said it may be attracted to light, and that monkeys in the Miami-Dade Zoological Park and Gardens were found rubbing their fur with them — a natural insect repellant. Grackles also have been seen rubbing the millipede under their wings.
“They’ve really moved their way up into our part of the world,” said Greg Rice, the marketing director for Hulett Environmental and Pest Control Services. “I’ve had them in my house too. It seems like they start moving with changes in weather.”
Rice said homeowners started calling about the millipedes several years ago. Hulett will do both a lawn treatment and perimeter treatment to keep the millipede population down, but the insecticides used kill on contact and don’t linger.
Rice recommends plugging up the millipede highway into the house by using weather stripping under doors, sealing cracks and entry points for utilities. Moving mulch or other yard debris away from the house can also help.
“If you are really ambitious, you could try to work some of the thatch out of your lawn,” Rice said. “But that’s a lot of work.”
Schall said invading insects are commonplace in Florida with as many as two new insect species per month finding their way into the state.
In the Florida Keys, where the yellow-banded millipede was first spotted, they’ve just become “part of the landscape.”
Kim Gabel, an environmental horticulture agent with Monroe County’s extension office, said people call when they step on a millipede, or see them crawling up their walls.
There’s also the concern about what they look like when dozens get smashed on a driveway or sidewalk.
“People get frustrated by the stains,” Gabel said. “Maybe we should paint our driveways the color of millipede guts.”