You found a bug. Now you want to know what it is, whether it matters, and whether you need to do something about it.
Identification is the step that determines everything after it. The same treatment that eliminates one species does almost nothing against another, and several of the most common misidentifications in Palm Beach County, Martin County, and St. Lucie County lead homeowners to spend months treating the wrong problem.
This is a starting point rather than a complete key. For each species below there is a short description, what its presence usually indicates, and a link to the fuller guide.
What to know first
Size and drama run in the opposite direction from actual risk in Florida. The large alarming insects are generally harmless, while the species that cause real structural damage and health concerns tend to be small and easy to walk past.
Where you found it matters as much as what it looks like. A cockroach in the garage and a cockroach in the kitchen are frequently two different species with two different treatments.
The most useful question is usually not what the insect is called. It is whether the population lives inside your house or outside it, because that single distinction determines where treatment has to happen.
Four species account for nearly every residential sighting here, and they divide cleanly into one that lives indoors and three that do not.
German cockroach.
About half an inch, light tan, with two dark parallel stripes running lengthwise behind the head. Does not fly and avoids light. This is the only Florida species that establishes large breeding populations inside walls and appliances, which makes it the one that requires interior treatment. Repeated sightings of small striped roaches in a kitchen or bathroom indicate an established population rather than a wanderer.
American cockroach.
Two inches or longer, reddish brown, with a pale figure-eight pattern behind the head. This is the palmetto bug, and it lives outdoors in mulch, palm crowns, and storm drains. One inside the garage after a storm is normal. Our palmetto bug guide covers why the nickname causes so much confusion.
Smokybrown cockroach.
Slightly smaller, uniformly dark mahogany with no pattern, and a strong flier drawn to light. Lives in tree canopy and soffit voids. Indoor sightings are flight-entry events rather than evidence of a colony.
Asian cockroach.
Nearly identical to a German cockroach in appearance, which is the problem. The difference is behavior: Asian cockroaches fly readily and move toward light, while German cockroaches do neither. Getting this one wrong means treating the interior for a species that lives in the landscape.
The full species breakdown is in our Florida cockroach identification guide, and our treatment guide covers the approach for each.
Four species cover most indoor ant activity across the region, and the tell is usually color pattern combined with trail behavior.
Ghost ants.
Very small at roughly 1.5 millimeters, with a dark head and a pale, almost translucent abdomen. Thin single-file trails along grout lines and countertops. By far the most common indoor ant here. Colonies operate across dozens of connected nesting sites, which is why spraying a trail fragments the colony rather than reducing it.
White-footed ants.
Slightly larger, entirely dark except for pale feet visible up close, and forming much wider trails than ghost ants. They do not share food the way ghost ants do, so conventional baits are less effective and the approach differs.
Carpenter ants.
Considerably larger, often bicolored with a reddish head and thorax against a dark abdomen, and usually seen individually rather than in trails. Their presence generally means moisture-damaged wood somewhere, which is the more expensive finding. Our carpenter ant guide covers where they nest and why.
Fire ants.
Reddish brown, small, and identified by the mound rather than the individual. Aggressive when the mound is disturbed. A lawn problem rather than a structural one.
Our tiny ant identification guide covers all four with the distinguishing features side by side.
The species that generate the most alarmed phone calls are the harmless ones.
Huntsman spiders are flat, fast, hold their legs out to the sides, and can reach a four inch leg span. Wolf spiders are stout and hairy, stay at ground level, and turn up after rain. Golden silk orbweavers sit in large golden webs outdoors and are what most Floridians mean by banana spider. Southern house spiders build messy webs in wall cracks, and the males get mistaken for brown recluse constantly.
None of those are medically significant. Widow spiders are the group that warrants caution here, and they are small enough that most people walk past them.
Three species, and the elevation where you hear them narrows it down before you ever see one.
Roof rats.
Slender with a tail longer than the body, large ears, and a pointed snout. They travel through tree canopy and enter at the roofline, so activity is heard overhead in the ceiling. This is the species behind most attic calls in South Florida.
Norway rats.
Stockier with a tail shorter than the body, small ears, and a blunt snout. They burrow at ground level and enter through low openings, so activity is heard along baseboards or in the garage.
House mice.
Much smaller, occupying wall voids, cabinets, and pantry areas rather than open attic space. They also fit through quarter-inch gaps, which means exclusion work has to close much smaller openings.
Droppings settle it faster than a sighting. Our droppings comparison guide covers size, shape, and pattern, and the full species guide is here.
This is the category where identification matters most, because damage accumulates silently.
Subterranean termites.
Enter from the soil and build pencil-width mud tubes on foundations and framing. They produce no visible frass, since galleries are packed with soil instead. Swarmer wings shed on windowsills after warm humid evenings are often the first sign.
Drywood termites.
Live inside the wood and push out frass: small, uniform, hexagonal pellets that look like coarse sand and accumulate below the infested wood.
Carpenter ants.
Get confused with both, and the frass tells them apart. Carpenter ant frass is coarse and fibrous like pencil shavings, with recognizable insect parts mixed in.
Our guide on termites in water-damaged wood covers how to distinguish all four, and the prevention guide covers what to do before any of it appears.
Bite location on the body is the fastest diagnostic, and it works better than trying to identify the insect.
Bites on ankles and lower legs, small and hard and itching for a week, point to fleas, because fleas live in carpet at floor level and jump upward. Clusters or short lines on arms, shoulders, and neck point to bed bugs. Scattered welts on exposed upper skin point to mosquitoes.
Our flea bite guide covers the distinctions in detail, and the mosquito guide covers why treatment does not hold as long as people expect.
Silverfish, earwigs, and springtails share one thing: they only live where it stays damp, which makes them more useful as indicators than as pests.
Silverfish are teardrop-shaped, silvery gray, with three tail appendages and a distinctive side-to-side movement. Earwigs have visible pincers that look threatening and are not dangerous. Springtails are tiny jumping specks on windowsills and bathroom floors.
None of them bite, sting, or carry disease. All of them mean an area of the house holds more humidity than it should. Our silverfish guide covers what their location tells you about the moisture source, and the broader moisture pest guide covers the rest.
Worth knowing before you treat something unnecessarily.
Antlions dig the small conical pits in dry sand and eat ants. Green lacewing larvae eat the aphids that ants farm. Mud daubers stock their mud tubes with spiders and are far less defensive than paper wasps. Anoles and geckos work through roaches and moths every night.
Our guide on beneficial insects covers which ones to leave alone.
If the species is still unclear, these narrow it down.
Is it damaging the structure?
Termites, carpenter ants, and wood-boring beetles belong in this category and warrant prompt attention.
Is it a health concern?
Mosquitoes, German cockroaches, rodents, ticks, and fleas belong here.
Is it eating other insects and staying out of the way?
That category does not need treatment. Most of what alarms people in a South Florida home falls into this group.
Identification from a photo takes about thirty seconds and frequently ends the conversation, because the answer is often that nothing needs to be done.
It is worth doing when the insect is small and striped, since German and Asian cockroaches look nearly identical and the treatments are opposite. When frass is involved, since the pellet shape separates drywood termites from carpenter ants. When you are finding the same species repeatedly in the same spot, which usually indicates something about the conditions there. And when the insect turned up in a room that has no obvious connection to outdoors.
If you found something and are not certain what it is, an inspection settles it and tells you whether treatment is warranted at all. Wise House Pest Control offers a free inspection across Palm Beach County, Martin County, and St. Lucie County.
1177 Hypoluxo Rd Suite C-31 Lantana, FL 33462
464 NW Peacock Blvd, Unit 106 Port St Lucie, FL 34986
Antlions, green lacewing larvae, mud daubers, and anoles all eat other insects and cause no damage. Treating them removes predators of the pests you are actually concerned about.
Where you hear activity narrows it down. Overhead in the ceiling usually means roof rats. Along baseboards or in the garage usually means Norway rats or mice. Droppings confirm it, since rat droppings run half an inch or longer while mouse droppings are the size of a rice grain.
Generally not. Huntsman spiders, wolf spiders, and golden silk orbweavers are all harmless despite their size. Widow spiders are the group of medical significance in Florida, and they are small rather than large.
The frass. Drywood termite frass is small, uniform, hexagonal pellets resembling coarse sand. Carpenter ant frass is coarse and fibrous like pencil shavings with recognizable insect parts mixed in. Subterranean termites produce no visible frass and build mud tubes instead.
Either a German cockroach, which breeds inside walls and appliances, or an Asian cockroach, which lives outdoors and flies toward light. Behavior separates them, since German cockroaches do not fly and avoid light. The treatments are opposite.
Start with where you found it and whether the population lives indoors or outdoors, since that determines where treatment has to happen. Size, color pattern, and behavior separate most species. For cockroaches and ants specifically, two pairs of lookalikes require different treatments, so identification matters more than it appears.
