One of the most commonly asked questions by homeowners is: “are spiders good to have around?” The answer is yes. Spiders are good to have around because they help control populations of other pests. Did you know that spiders eat the more than the entire weight of the human population in bugs each year? I’d say that’s a good friend to have.
Florida is home to a vast variety of spiders. From inside your home to your backyard, to the walking trails through your favorite park, spiders are some of the commonly seen, yet misunderstood creepy critters out there. We celebrate them at Halloween, and even make movies about them, yet fear them the rest of the year. Only about 5% of the population suffers from acute arachnophobia. But to quote the adage, “they’re more afraid of you than you are of them” isn’t a far leap. Spiders tend to avoid just about everything. They do not lurk to spook you; they are merely just hunting for food. Yes, it can be a little annoying to walk into a spider web, and it may make your skin crawl. Still, they aren’t looking to entrap you as a meal; you just happened to walk into the snare they set for the mosquito that’s been buzzing around your head.
Of the forty thousand different species of spiders, you’ll only find about 60 unique species in Florida. Some are house spiders; some prefer to live in the woods, while others are beneficial to your garden. Not all spiders spin webs; some are ambush predators preferring instead to lie in wait and attack their prey. Most spiders prefer to live a solitary life. However, there are some species that more social than others. Spiders belong to a group called arachnids, which include scorpions, mites, and ticks. This group of creatures is defined as those with two body parts, eight legs, and the inability to chew. Arachnids also do not have wings nor antennae. Spiders are mostly grouped by the type of webs they spin. The main groups of web-spinning spiders include orb-web, funnel-web, nursery-web, and tangle-web spiders. Looking at a spider web is a study in the intricacy of craftwork that these creatures are capable of.
Nearly all spiders are venomous, but only a few are dangerous to humans, including two types found in Florida: widow spiders and recluse spiders. Those in the widow spider group are found worldwide, but the recluse is not native to Florida. In the Sunshine State, we have three native species of widow spiders and one introduced species. Three species of recluse spiders have also been introduced to Florida.
Of the four widow spiders found in Florida, the black widow is the most feared because of its bite. There are three species of black widow found in the United States: the southern black widow, the northern black widow, and the western black widow. All of these spiders can be identified by the hourglass red shape found on the abdomen; however, some individuals will have variations of this mark. While black widow spider bites are rarely fatal, they are extremely painful and cause additional symptoms, including sweating, nausea, vomiting, and muscle cramping. If left untreated, symptoms can last three to five days. Brown widow spiders, also found in Florida, do not have the necessary amount of venom to inflict a wound beyond the local bite area. There may be a small amount of pain, swelling, and a red mark around the puncture wound. The last species of widow found in Florida is the red widow spider. Unless you are a small animal caught by this spider, the symptoms are similar to that of a black widow. Symptoms can include hypertension (high blood pressure), sweating, vomiting, and abdominal tenseness comparable to that of appendicitis. The worst of the symptoms will pass in the first 8-12 hours but can also last for up to five days. Antivenin is not usually necessary but can be used as a precautionary measure. Those most vulnerable populations to fatality are the very young and the very old.
Recluse spiders are far more dangerous. In Florida, you can find three species of recluse spiders: The brown recluse, Mediterranean recluse, and Chilean recluse. None of these species are indigenous to the state. The most common species are the brown recluse. The violin-shaped mark on their back can quickly identify them. Recluse spiders are commonly found in the house, though they are considered an outdoor spider. The initial symptoms of a recluse spider bite are like those of a widow and include fever, nausea, vomiting, sweating, and a state of general discomfort. However, with a recluse bite, an open sore with necrosis (tissue breakdown) will begin to develop within a week. The other problem with a recluse bite is that you may not know that you’ve been bitten right away. Unlike widows, there is not immediate sharp pain associated with a bite, much like that of a bee or wasp sting. Symptoms usually begin to appear about 2-8 hours after the bite occurs. Recluse bites have never been reported to be fatal. The good news is that these species of spiders get their name “recluse” because they tend to be quite shy, as most spiders are. Spiders only bite when they feel threatened. Widows and recluses alike are unlikely to bite unless they feel trapped or otherwise threatened and are already pressed against human skin. When moving items outdoors, you can avoid widow and other spider bites by wearing gloves.
One of the most common spider species is the “Daddy Long Legs.” This species is also one of the largest spiders found in Florida, thankfully. Daddy Long Legs is a nickname attributed to several different species. Still, humans most often come into contact with those known as cellar spiders. With a leg span of about 3,” these small-bodied arachnids are entirely harmless. They are, in fact, a venomous spider, but like many spiders, they rarely bite unless threatened. A common myth is that Daddy Long Leg spiders are the most venomous to humans, but their fangs are too short to penetrate human skin. This legend is utterly untrue. The only type of non-venomous spiders are those in the Uloboridae family, and cellar spiders belong to the family Pholcus.
There are two species of typical “house” spiders found in Florida homes: the common house spider otherwise known in foreign countries as the American house spider and the Southern house spider. The common house spider is dark grey to black and has white markings, and the legs are yellow to brown. The abdomen is usually higher than it is long. These spiders typically make tangle webs in the corners of homes and are one of the significant contributors to “cobwebs.” They eat a variety of prey, including German cockroaches. The male Southern house spider is very often mistaken for brown recluse spiders; however, females tend to be grey or charcoal. Their silk used to make webs is often described as being like Velcro for its adhesive properties. They prefer to construct webs in recesses of buildings like windowsills, shutters, and other overhangs. This spider especially likes spaces between masonry in buildings. Males do not spin webs; instead, they seek out females and “move-in” with them. These spiders also create tangle-webs, which look rather messy.
One of Florida’s largest spiders, the Wolf Spider, can be commonly found in the household, even though it is considered an outdoor spider. These spiders are similar in leg span to Daddy Long Legs with typical species having an average 2” leg span. Many people fear wolf spiders because of the hair on them, often mistaking them for a form of tarantula and therefore presume them to be dangerous. This species is an ambush predator and does not spin a web. They sometimes dig burrows but are often found under debris in the yard. Like any outdoor spider, they find their way inside homes through cracks in foundations or walls and continue to hunt prey. As is with most spiders, they do not seek out humans to bite, but will do so if threatened. A wolf spider bite can be likened to the pain incurred with a bee sting.
Spiders are a good thing to have around, and most are no threat to humans. Only those with allergies should be worried if any spider bites them. Spiders help humans by consuming copious amounts of other pests. Having dispelled some of the common myths around spiders, continue to part two of this series to learn about beneficial garden spiders and those that you might encounter on your next outdoor adventure.
Spider Fun Facts
- It has been said that spiders have 48 “knees.” Spiders have eight portions to their legs, so if you multiplied eight legs by the seven connecting joints, they actually have 56!
- Cobwebs are just abandoned spider webs. If there is a lack of bugs, spiders will move to a new location with better hunting grounds.
- Spider silk is not stronger than steel but does have comparable tensile strength (the point at which it can be stretched before breaking)
- Common pet Tarantulas are not at all dangerous to humans. The greatest threat posed to humans is the hairs on the abdomen, which can be irritating to human skin and cause itching or rashes. You are far less likely to be bitten by a tarantula than your neighbor’s golden retriever.
Florida Department of Agriculture and Consumer Services: https://www.fdacs.gov/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Pest-Alerts/Venomous-Spiders-in-Florida
University of Florida Entomology and Nematology Department:
National Geographic: https://www.nationalgeographic.com/animals/invertebrates/group/wolf-spider/