Spiders found in South Florida
Crab spiders are so named because they hold their legs to the side in a crab-like fashion. Most crab spiders are less than 1 cm (0.4 in) in length, although the giant crab spider may reach 2.5 cm (1.0 in). Crab spiders do not spin webs to trap prey, but hunt on the open ground or on vegetation or flowers. In keeping with their ambush style of attack, many crab spiders are well camouflaged, blending in with their backgrounds. Some resemble tree bark, leaves, or fruits; others appear to mimic bird droppings. Though their chelicerae, or jaws, are rather small and slender, many crab spiders possess potent venoms that quickly immobilize their prey. Flower spiders, a particular type of crab spider, rest on flowers and remain motionless for long periods of time with their front two pairs of legs extended in readiness. crab spiders do not wrap their prey in silk after biting, but instead remain with the immobilized prey until they have sucked it dry.
Jumping spiders do not construct webs, but actively hunt prey during the day, pouncing on their luckless victims. Many are brightly colored. All species are small, usually less than 15 mm long. They are easily identified by their eye arrangement, which is in three rows. Although jumping spiders do not make webs to capture prey, they do use silk. Hunting spiders trail a dragline behind them to break their fall in case they miss a jump. Silken nests, ellipsoid structures with an opening at each end, are used for resting at night, molting, and egg-laying. Juveniles may make their nests in the tops of herbs or in rolled leaves, while subadults and adults frequently make their nests along the inner mid-veins of palm fronds.
Golden Silk Spider
In Florida and other southeastern states, the golden silk spider, or as we call them the banana spider, is a large orange and brown spider with the feathery tufts on its legs is well know to most native southerners. It is particularly despised by hikers and hunters, as during late summer and fall the large golden webs of this species make a sticky rap for the unwary. The female is distinctively colored, and is among the largest orb-weaving spiders in the country. The female is 25 mm to 40 mm long and has conspicuous hair tufts on her long legs. Males are about 4 mm to 6 mm long, dark-brown, and are often found in the webs of females. These spiders feed primarily on flying insects, which they catch in webs that may be greater than a meter in diameter.
Spiny Orb Weaver Spider
The spiny orb-weaver spider is one of the most colorful and easily recognized spiders in Florida. The dorsum of the abdomen is usually white with black spots and large red spines on the margin. Females are 5 mm to 10 mm long and 10 mm to 14 mm wide. The webs typically contain tufts of silk, which may prevent birds from flying into them. The famous spider from Charlotte’s Web is a barn orb-weaver spider. Orb weaving spiders produce the familiar flat, ornate, circular webs usually associated with spiders.
Black And Yellow Argiope Spider
The argiope spiders are a large and distinctive group. Their large, conspicuous webs can often be seen along the edge of woodlands. The black and yellow argiope can reach a length of 25 mm. Its characteristic silver carapace and yellow-and-black markings make it easy to identify. Argiope spiders tend to hang head down in the middle of a medium-sized web that has thickened, zigzag bands of silk in the center. These spiders have relatively poor vision, but are quite sensitive to vibration and air currents. Males communicate with potential mates by plucking and vibrating the females’ webs.
Green Lynx Spider
This spider is commonly encountered on shrubs, weeds and foliage. The female is 12 mm to 20 mm long, while the male seldom gets larger than 12 mm. For a large and brightly colored spider, the Green Lynx is rarely noticed. This spider does not actively hunt, but instead lies in wait for unwary bees, flies, and other insects. The spiders almost always choose light green foliage on which to position themselves. They prefer to be near flowers, but still tend to be perfectly camouflaged. The body is a vivid, almost transparent green, with red spots and some white markings. The legs are long, slender and covered at intervals with long black spines. These spiders have good eyesight and hunt and stalk their prey during the daytime. They spin no webs but sometimes anchor themselves with silk. They are important predators of caterpillar pests of row crops.
Wolf spiders are very common and usually found on the ground, where they are well-camouflaged. The hairy, fleet, wolf spiders are very common outdoors under leaf litter, rocks, and logs. When they come inside, they normally stay on the ground floor and are active in dim light. Large Wolf spiders often frighten people. If handled, they give a painful bite but it is not dangerous. The Carolina wolf spider, at 25 mm to 35 mm, is the largest in the United States. These spiders do not spin webs but some dig burrows or hide under debris. Like other hunting spiders, they have good eyesight and are sensitive to vibrations.
Long Jawed Orb Weaver Spider
These spiders characteristically cling to a support with their short third pair of legs while holding their remaining, much longer, legs extended in front of and behind the body. They spin small webs that are 8″ to 12″ in diameter and catch small flying insects. They are often found in association with foliage bordering water. Long-jawed Orb Weavers are named because of their large chelicerae (fangs), which are, in some species, longer than the spider’s cephalothorax. Long-jawed orb weaver are not considered pests, and their bites are rare and are not dangerous except to allergic individuals.
Brown Recluse Spider
Known as violin, fiddleback, or brown spiders. These venomous spiders are found worldwide, most commonly in the tropics, with some species reaching temperate latitudes. No species of recluse spiders are native to Florida, but three species have have established populations in scattered locations throughout the state. The brown recluse spider, is frequently reported in Florida as a cause of necrotic lesions in humans. For example, in the year 2000 alone the Florida Poison Control Network had recorded nearly 300 alleged cases of brown recluse bites in the state. The brown recluse has been found in Alachua, Bay, Duval, Jefferson and Leon counties, with most counties in central Florida having reports of alleged brown recluse spider bites. Many wounds are erroneously attributed to this spider, but there are multiple other causes of necrotic wounds.
Recluse spiders are medium-sized (6-12 mm body length), with uniformly-colored abdomens that can vary from a tan to dark brown. The males and females are about the same size. The body, including the legs, is a little wider than a quarter dollar coin. In many species there is a characteristic darkened violin-shaped pattern which occurs on the front half of the head region. However, other unrelated spiders may have a pattern which can easily be mistaken for the violin. A more useful method of determining recluse spiders is by using the eye pattern. Most spiders have eight eyes arranged in two rows of four, but recluse spiders have six eyes arranged in three pairs (dyads), with one anterior dyad and a lateral dyad on each side. Some related spiders, particularly spitting spiders (which have a unique domed head region), have a similar eye pattern, but these are otherwise different. Recluse spiders make a protective silken retreat, but they are usually hunters that leave the web in search of prey. They can be abundant in human structures.
The Brown Recluse inhabit the south and south-central states from Georgia through Texas and north to Wisconsin. A few years ago it was common belief that there were no brown recluse spider populations in neither California or Florida. Unfortunately this is changing, recent evidence suggest that the brown recluse spider is expanding across the US and there may already be a thriving population in both Florida and California.
Brown Recluse spiders feed on cockroaches and other insects. They do not spin webs to catch prey but instead hunt for their prey or wait until an insect comes in close proximity to them. Mobile prey like houseflies and relatively harmless prey are held down with the initial bite while the venom does its work. With prey that might be more harmful to the spider, such as other spiders or ants, they will lunge and bite the prey in a vulnerable area and immediately back away while the venom acts to quickly paralyze them. The spider then moves in to feed. The same venom that acts to liquefy an insect’s innards for consumption also causes the “flesh rotting” appearances in human wounds. The Chilean Recluse species from South America has been found in the suburbs of Los Angeles, and in Polk County, Florida. The Chilean Recluse is believed to be the most toxic Recluse spider and is implicated in a number of deaths in South America.
Brown recluse spiders usually bite only when they become trapped next to the victim’s skin. Bites occur either when sleeping humans roll onto the spider or put on clothes into which the spider has crawled. Typically bites occur under clothing, mostly on the thigh, upper arm, or lateral torso, less often on the neck.
Reactions to a bite vary from no noteworthy symptoms to severe necrosis or systemic effects, including death or loss of limbs. Discomfort may be felt immediately after the bite, or several hours may pass before any local reaction to the bite occurs. The first is the amount of venom injected by the spider. Like some venomous snakes, spiders are known to sometimes give “dry” bites, with little or no venom injected. The second variable is the sensitivity of the victim. Some people are simply more prone to have a severe reaction in instances where another person might only have a slight reaction. Typical symptoms are as follows: Symptoms start two to six hours after the bite. Blisters frequently appear at the bite site, accompanied by severe pain and pronounced swelling. A common expression is the formation of a reddish blister, surrounded by a bluish area, with a narrow whitish separation between the red and blue, giving a “bull’s-eye” pattern. By 12 to 24 hours, it is usually apparent if a recluse spider wound is going to become necrotic because it turns purple in color; if necrotic symptoms do not express by 48 to 96 hours, then they will not develop. If the skin turns purple, it will then turn black as cells die. Eventually the necrotic core falls away, leaving a deep pit that gradually fills with scar tissue.
Brown Widow Spider
The brown widow is established pretty much throughout the Florida peninsula. It is found most often south of Daytona Beach along the coast. The brown widow builds its web in secluded, protected sites around our homes, often very near our presence. It has a fondness for buildings but will construct its web in all kinds of man-made structures, and even vegetation. Some typical sites include inside old tires, empty containers such as buckets and nursery pots, mail boxes, entry way corners, under eaves, stacked equipment, cluttered storage closets and garages, behind hurricane shutters, recessed hand grips of plastic garbage cans, underneath outside chairs, and in branches of shrubs.
Because brown widow spiders vary from light tan to dark brown or almost black, with variable markings of black, white, yellow, orange, or brown on the back of their abdomens, brown widows are not as easy to recognize. The underside of the abdomen, if you can see it, contains the characteristic hourglass marking. Unlike the black widow, the hourglass is orange to yellow orange in color. The brown widow is also slightly smaller than the black widow. The egg sac looks like an old naval mine or a sandspur seed.
Brown widow spiders are extremely timid; the only bites reported have resulted from a spider being accidentally trapped against the victim’s body. Brown widow spider bites are however becoming more common. The venom of the brown widow may be twice as potent as the black widow, experts believe, but the brown widow is less inclined to inject larger amounts of venom. Brown widow bite symptoms can include pain, rigidity in the muscles of the abdomen and legs, swelling, nausea, vomiting and in severe cases a sharp rise in blood pressure. Generally, the symptoms of the brown widow tend to stay localized to the bite site, whereas the black widow’s symptoms are more widespread.
Black Widow Spider
The southern black widow is the most widespread widow spider in Florida. It’s glossy black and has a complete hourglass marking on the underside of the abdomen. The black widow spider’s body is about 1/4-1/2 inch long and 3/4 to 1 and ½ inches wide when legs are spread out. The northern black widow has the same general appearance, but has two red triangles resembling an hourglass and a row of red spots on top of the abdomen. The northern species is found west of Tallahassee, primarily in forests, with its webs 3 to 20 feet above the ground. It’s usually found outdoors under rocks and boards, and in and around old buildings.
The black widow spider’s venom is a potent neurotoxin and is considered the most venomous spider in North America. However, the female injects such a small dose of venom that it rarely causes death. They are timid and solitary, and often bite only when disturbed. All encounters with humans can be attributed to the female. The bite of the black widow and other widow spiders usually feels like a pin prick. The initial pain disappears rapidly, leaving local swelling and two tiny red marks. Muscular cramps in the shoulder, thigh and back usually begin within 15 minutes to three hours. In severe cases, pain spreads to the abdomen, the blood pressure rises, and there is nausea, sweating and difficulty in breathing. Death may result, depending on the victim’s physical condition, age and location of bite. Death seldom occurs if a physician is consulted and treatment is prompt.
Red Widow Spider
The red widow has a black abdomen with a single flattened red triangle on the underside. On the back are rows of red spots, each of which are surrounded by a yellow circle. The head region and legs are red-orange in color. The red widow spider’s web begins as a typical tangle web in the interior of a small palm or palmetto, but then continues as a sheet of silk onto one of the lateral open leaves. Red widow spiders are endemic to Florida. It occurs in sandpine scrub from Marion County to Martin County. Because of both its rarity and its beautiful coloring, the red widow spider is a collector’s item for spider specimen collectors. Little is known of its bite, but its venom is probably quite toxic to mammals.