Florida’s warm, humid climate supports a long list of biting insects and arachnids, many of them active year-round. Mosquitoes, no-see-ums, yellow flies, fire ants, ticks, and chiggers are the most common culprits, and each one leaves a distinctive mark. Here’s what you’re likely dealing with and how to handle it.
Mosquitoes
Florida is home to roughly 90 mosquito species, but four are responsible for most human bites around homes. The yellow fever mosquito and the Asian tiger mosquito are daytime biters that breed in small containers of standing water, from flowerpot saucers to discarded tires. The southern house mosquito is more active at dusk and overnight, breeding in ditches and storm drains.
These aren’t just a nuisance. The yellow fever mosquito can transmit dengue, Zika, chikungunya, and yellow fever. The Asian tiger mosquito spreads dengue and eastern equine encephalitis. The southern house mosquito is the primary carrier of West Nile virus and St. Louis encephalitis in the state. These diseases are uncommon in Florida, but outbreaks do happen, particularly with dengue in South Florida. Mosquito bites typically produce a raised, itchy welt within minutes that fades over a day or two.
No-See-Ums (Biting Midges)
If you’re getting bitten but can’t see anything, no-see-ums are the likely cause. These tiny flies, barely 1 to 3 millimeters long, are especially common near coastal marshes, mangroves, and wet grasslands. Northern Florida has the greatest diversity of species, but coastal populations stretch the entire length of the state.
Most no-see-ums bite during dusk, nighttime, or early morning. In cooler weather or along the coast, though, they’ll bite in broad daylight. The bite itself produces a sharp stinging or burning sensation with a small red spot. For most people, discomfort lasts minutes to hours. If you’re hypersensitive, the itching can persist for two to three days. Standard window screens don’t stop them because they’re small enough to pass right through. Finer mesh screens (at least 16 holes per inch) or staying indoors during peak activity are the most reliable defenses.
Yellow Flies and Horse Flies
Yellow flies are one of Florida’s most aggressive biting pests. They’re active from March through November, with a peak season from April through June. Only the females bite, and they do it silently. You typically won’t notice the fly until you feel a sharp, cutting pain, because they slice the skin with blade-like mouthparts rather than piercing it like a mosquito.
Yellow flies are most active in late afternoon and on cloudy days, and they tend to stay near forests and large bodies of water. They’re one of the few biting flies that will follow you indoors. Bites often produce large, itchy swellings that can last for days. Some people develop increasing sensitivity with repeated exposure, where each subsequent bite triggers a worse reaction. Horse flies and deer flies, close relatives, behave similarly but are larger and generally found in more rural areas.
Fire Ants
Imported red fire ants are everywhere in Florida, from suburban lawns to parks and roadsides. Their mounds are easy to miss until you step on one, and the response is fast. A fire ant grabs your skin with its jaws, then curls its body to drive its stinger in repeatedly, pivoting in a circle. A single ant can deliver seven or eight stings before you brush it off, and dozens of ants often attack at once.
The progression is predictable. First comes an intense burning sensation. Within about an hour, itchy red bumps appear in a circular or semicircular pattern. After several hours, those bumps turn into small blisters. By the next day, the blisters fill with white or yellowish fluid, forming the characteristic pustules that are the hallmark of fire ant stings. These typically resolve within seven to ten days. Resist the urge to pop them, as broken pustules are prone to infection.
Ticks
About 30 tick species live in Florida, but only a handful regularly bite humans. Ticks are active year-round in the state’s subtropical climate, with peak activity between April and August.
The lone star tick is the most common human-biting species in Florida. Females are easy to identify by a single white dot on their backs. Beyond the usual tickborne infections like ehrlichiosis and tularemia, lone star ticks are responsible for alpha-gal syndrome, an allergic reaction to red meat and dairy products. It develops when a tick transfers a sugar molecule called alpha-gal into your bloodstream during feeding, and your immune system later reacts to that same molecule in mammalian meat. North Florida carries a higher risk, but lone star ticks are distributed statewide.
Black-legged ticks (deer ticks) transmit Lyme disease, though cases acquired within Florida are relatively uncommon compared to the Northeast. Brown dog ticks and American dog ticks can carry Rocky Mountain spotted fever, which is rare in the state, with roughly a dozen cases reported per year. Gulf Coast ticks, found in coastal prairie and tall-grass habitats, carry a milder relative of Rocky Mountain spotted fever.
If you find a tick attached, remove it with fine-tipped tweezers by grasping as close to the skin as possible and pulling straight out with steady pressure. Save the tick in a sealed bag if you develop symptoms in the following weeks.
Chiggers
Chiggers are microscopic mite larvae that live in tall grass, brush, and leaf litter. In Florida, they’re commonly associated with areas under live oaks and around Spanish moss, though the moss itself isn’t the problem. Chiggers are ground-dwelling, so moss only harbors them after it falls to the ground and sits in contact with soil.
Unlike ticks, chiggers don’t burrow into your skin or feed on blood. They inject digestive enzymes that dissolve skin cells, then feed on the liquefied tissue. They tend to cluster where clothing fits tightly against skin: ankles, waistbands, and behind the knees. The bites produce intensely itchy red welts that can take one to two weeks to fully resolve. The itch is often worse than any other common Florida bite.
Bed Bugs and Fleas
Bed bugs are indoor pests found in hotels, apartments, and homes throughout the state. They feed at night, leaving clusters or lines of small, red, itchy bites, often on the arms, shoulders, and neck. They don’t transmit diseases, but infestations are notoriously difficult to eliminate without professional treatment.
Fleas are most common in homes with pets but can also live in sandy soil outdoors, particularly in shaded areas. Their bites appear as small red dots, usually on the lower legs and ankles, and itch intensely. In Florida, fleas are active year-round and can build large populations quickly in warm months.
Protecting Yourself
Repellents containing DEET (up to 30 percent concentration), picaridin, or oil of lemon eucalyptus are effective against mosquitoes, no-see-ums, and chiggers. Higher concentrations of picaridin also repel ticks. DEET and picaridin can be applied to both skin and clothing, while permethrin is a separate product meant only for treating clothing, shoes, and gear. It kills ticks and other insects on contact and lasts through several washes.
For no-see-ums and mosquitoes, timing matters. Avoiding outdoor activity during dusk and dawn eliminates the peak biting window for most species. Light-colored, long-sleeved clothing helps with yellow flies and horse flies, which are attracted to dark colors and movement. After spending time in wooded or grassy areas, check your body thoroughly for ticks, paying close attention to the scalp, behind the ears, and the groin area.
When a Bite Needs Medical Attention
Most Florida bug bites are uncomfortable but harmless. The signs that something more serious is happening include a reddish streak extending outward from the bite, pus draining from the wound, or blisters spreading beyond the original site. These suggest a secondary bacterial infection.
A severe allergic reaction is less common but requires emergency care. Warning signs include hives spreading beyond the bite area, swelling of the tongue or throat, difficulty breathing or swallowing, dizziness, a rapid pulse, or nausea and vomiting. Swelling that expands beyond four inches from the bite site is another indicator. People who have had a severe reaction to any insect bite or sting in the past should carry epinephrine when spending time outdoors.