Contrary to Popular Belief, Brown Recluse Spiders Are Rare in Florida — and Severe Bites Are Even Rarer

The brown recluse has a reputation for moving faster than the spider itself. In Florida, it is often attributed to mysterious injuries, nighttime bites and household infestations.

But a statewide survey published in the Journal of Medical Entomology found breeding populations in only 19 of 220 properties surveyed for suspected activity. In controlled laboratory tests, the spiders only bit under extreme stress – and when bites were checked, significant tissue damage was rare.

“This research shows that brown recluse spiders are not the bogeyman everyone makes them out to be,” co-author Louis Coticchio said in a press release. “They do not swarm throughout Florida, infiltrate homes and attack. Rather, they are misunderstood and want to be left alone, while rarely showing signs of aggression, even when provoked.”

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Brown recluse spiders remain very localized

The brown recluse (Loxosceles recluse) is native primarily to the Midwest and parts of the Gulf Coast and is not considered endemic to Florida. Yet reports of infestations regularly circulate online and in local communities, creating the impression that the spider is common throughout the state.

To evaluate this hypothesis, researchers surveyed properties across Florida where recluse activity had been reported. Confirmed breeding populations – in this case, Mediterranean recluse spiders, a closely related invasive species – have been found at just 19 sites, most concentrated in central and northern Florida.

Even within properties checked, population sizes varied, from a single spider to 171 individuals. The researchers found no evidence of widespread dispersal beyond these localized groups.

Established colonies remain geographically confined rather than widely distributed across households and neighborhoods.

Reluctant to bite, even when disturbed

Much of the spider’s reputation rests on its bite. To test defensive behavior under controlled conditions, the researchers applied gradual pressure to individual spiders using gel-tipped instruments. This method allowed the team to simulate disruptions consistently.

Wolf spiders were tested under identical conditions for comparison. When provoked, wolf spiders bite in about 80% of trials. Brown recluses, on the other hand, bite primarily when under severe stress, such as being squeezed or knocked over. Under lighter disturbances, bites were rare.

The comparison highlights a notable difference in defensive response. Rather than striking quickly, the brown recluse appears more tolerant of low-intensity disturbances and only reacts defensively under intense physical stress.

Serious reactions are rare and often misdiagnosed

The final question concerned necrosis, or tissue damage, often described in alarming terms in online accounts and anecdotal reports.

The study found that most verified recluse stings result in mild, self-limiting skin reactions. Typical symptoms include redness, burning, or small blisters that heal over time. When tissue damage occurs, it is usually superficial, about half a centimeter deep, and limited to the upper layers of the skin. It usually does not extend into muscles or bones.

Extensive necrosis is rare. Serious injuries frequently attributed to solitary bites may instead result from bacterial infections, including staph. Since many skin lesions are diagnosed without a confirmed spider specimen, misattribution can reinforce the spider’s outsized reputation.

“I’m not saying they are completely harmless, but rather they are reluctant to bite, and the percentage of encountering them in Florida is extremely low,” Coticchio said in the press release.

Overall, the results challenge the image of the brown recluse as a widespread and aggressive domestic threat. The species exists in localized pockets of the state, rarely bites under ordinary circumstances, and is often blamed for injuries it did not cause. Its reputation, as the facts show, has become larger than its actual footprint.

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