The 2 Most Poisonous Spiders in Florida

There are many different types of spider in Florida. Some of them, such as golden orb spiders, are mildly venomous and have painful bites, but their venom is too weak to be life-threatening to human beings (although in rare circumstances, it can cause allergic reactions). The most poisonous spiders in Florida belong to one of two types: they are basically either a species of widow spider, or a species of recluse spider. These are the only two types of spider found in Florida that have venom powerful enough to be dangerous to people.

You can minimize the chances of being bitten by being aware of the types of places where both types of spider might be found, and also by taking appropriate precautions, such as wearing gloves when reaching into recesses and places that you can’t see, where spiders might be hiding. Both types of spider can take up residence in old clothing that you haven’t worn for a long time. Other places where you should exercise caution is reaching into storage boxes, onto shelves in sheds, or when grabbing bundles of firewood – essentially places where you can’t see where you are putting your hands.

There are four species of widow spider that you might find in Florida, three of them native and one of them introduced. The fours species are: the southern black widow (Latrodectus mactan); the northern black widow (Latrodectus various); the red widow (Latrodectus bishopi); and the brown widow (Latrodectus geometricus).

Typically, a female widow spider has a glossy, jet black body and a bright red mark on its abdomen that is shaped like an hourglass. The males are usually gray or brown. The females are much bigger than the males, with the females measuring between 8 and 15mm and the males being only a quarter of the size. Widow spiders are nocturnal and build irregular, tangled, three dimensional webs, where they rest during the daytime. Widows will often hang upside down near the center of the web, until they detect an insect getting caught (usually by sensing vibration, rather than by sight), when they will run over and bite the insect, then cover it in silk.

The female widow is the most poisonous of the two genders, as its venom sacs are much bigger. The bite of the male is not generally considered to be dangerous. Symptoms of a widow bite generally start between one and three hours after the bite and can include: intense pain, muscle cramps, nausea, sweating, and vomiting. The venom initially just effects the area of the bite, but is spread by the lymphatic system and then the bloodstream around the body. The symptoms can last from 3 to 5 days, but a bite is rarely fatal if treated.

Widow spiders are generally timid and try to escape from humans if they feel threatened. They usually only bite defensively, occasionally when a female is protecting eggs, but mainly when they are accidentally pressed or pinched – this can happen if, say, someone puts on an old glove or shoe and there is a widow spider inside it, or if they feel under an object where a widow is hiding.

Recluse spiders are also known as brown spiders, violin spiders, fiddle-back spiders, or reapers. They are found in warmer places around the world, typically in tropical climates. They are normally between 6 and 12mm in size and are brownish in color, often with a darker, violin-shaped marking on its back. The mark is what gives the spider its “violin” and “fiddle-back” names, but there are other types of spider with similar looking markings. This can cause confusion when it comes to identifying them, so the best way to tell if a spider is a recluse is by its eyes - most spiders have eight eyes arranged in two rows but the recluse has six eyes arranged in pairs.

Recluse spiders are not native to Florida, but individual spiders from three different species of recluse are occasionally found. Because there are so few of them, the likelihood of getting bitten by a recluse spider in Florida is very small. The effects of a bite can vary greatly in intensity, from virtually no effect, all the way up to death (in extreme circumstances). As with widow spiders, a typical way to receive a recluse bite is for a person to put on an item of clothing that hasn’t been worn for a long time with a spider insider it, or reach into a place where a spider is hiding. Early symptoms of a recluse bite usually begin between two and six hours after the bite and include: blistering, intense pain, and swelling. In serious cases, the blistering can develop into an open sore, known as a “necrotic skin lesion”, or have systemic effects on vital organs.

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