Spiders in the Everglades

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A great variety of plants and animals inhabit the Florida Everglades, and spiders are among the most numerous. More than 20,000 spiders live on each of the 2 million acres, making it almost impossible for a visitor to avoid close-up encounters with a few of them. Far more spiders go about their work unnoticed. Spiders are an essential and largely unobserved part of the complex and diverse Everglades ecosystem.

Everglades Ecosystem

Although nearby human population growth and consequent demands on its resources has heavily impacted the Everglades, the area remains a varied maze of distinct habitats, connected by waterways and wetlands. Abundant natural resources provide food and shelter for more than 350 species of birds alone, as well as numerous species of reptiles, amphibians and mammals, insects and spiders. Like most species, spiders are both prey and predator, doing their part to keep other populations in check by using them as food.

Orb-Weaving Spiders

The many species of orb-weaving spiders are differentiated by their physical appearances. These spiders are most often encountered by Everglades visitors, who may run face-first into an orb-weaver's web if they are inattentive. These large but harmless spiders weave an intricate, large geometrical web, carefully suspended above the forest floor as a net to catch prey. The spider waits at the center of the web, although she will rapidly retreat to hide in the leaves of the nearest supporting tree branch if she senses danger. The non-aggressive golden silk spider, Nephila clavipes, sometimes called the banana spider, is the most common of the Everglades orb weavers. Featuring tufts of hair on the legs, the golden silk spider is brown, orange, yellow and white. The female is much larger than the male. Webs of female golden silk spiders can reach more than a meter in diameter. She will eat insects of all kinds that happen into her net, including dragonflies. Wasps are her natural enemies. The spiny orb weaver, Gasteracantha cancriformis, is another easily recognized spider of the Everglades. Among the smallest of the weaving spiders, the spiny orb weaver is named for the six spines prominently displayed on a body that is is wider than it is long. In Florida, this spider usually has a white body with black spots and red spines, but the colors can vary. The webs are ornate and circular, and some have silken tufts that help warn off birds that otherwise might damage the webs by flying through them. Spiny orb weavers generally build their webs between 1 and 6 meters above the ground, and catch prey such as beetles and moths.

Red Widow Spiders

A well-known poisonous spider found throughout the United States as well as in the Florida Everglades is the black widow. The far less known red widow spider (Lactrodectus bishopi) is found only in one small habitat within the Everglades, and is considered the most rare widow spider in the United States. These spiders are large, growing to about one and a half inches; the bright-red color is unmistakable. They are extremely venomous. The red widow's diet consists of crickets and other large insects, which she captures in webs built in scrub palmetto plants. All widow spiders are dangerous to humans, delivering a powerful and painful bite in self-defense. With proper medical treatment, the bite will leave no lasting effects.

Wolf Spiders

The wolf spiders (Hogna spp.) are numerous, large, and found mostly on or in the ground. They are found throughout the United States, and are numerous in the Everglades. Wolf spiders prefer burrowing to building webs, and they use their sensitivity to vibrations and movement to hunt down prey. Hogna hunts at night, preferring to spend the day resting in an underground borrow. The spider's coloring allows her to blend into her surroundings, giving her a better chance for a successful kill.

Jumping Spiders

Like the wolf spider, jumping spiders are active hunters that do not build webs to capture their meals. Rather, they pounce on their prey like larger predators. While jumping spiders don't use webs for hunting, they use their silk to create nests each night, and as a safety string to save themselves from long falls. They also create nests when they lay eggs and molt, and these nests can typically be found on plant leaves. In appearance, these small spiders are most often black and white, and can be identified by their three rows of eyes. The most common jumping spider species encountered in Florida, Phidippus regius, is often found near fields and other open areas. Adults prefer palm trees and palmettos, while young jumping spiders can be found on or near the ground. The canopy spider, Phidippus otiosus, is a jumping spider who lives high in the trees, where moss hangs from the branches. Flies, bees, moths, and extremely tiny insects make up the majority of jumping spider prey, but they are also known to prey on the bugs that cause harm to sugar cane crops.

Crab Spiders

So named because they resemble the ocean-dwelling creatures in leg positioning, the spiders termed crab spiders actually belong to many species in more than one genus. Like wolf spiders and jumping spiders, they rely on actively hunting their prey rather than passively waiting for webs to catch their next meal. Although they are small, crab spiders are armed with a strong venom that allows them to quickly subdue their prey. Crab spiders are able to capture and eat prey much larger than they are, such as cockroaches and butterflies. Many different types of crab spiders live in the Everglades, among them the flower crab spider (Misumenops celer), and the twig crab spider (Timarus rubrocinctus). Most crab spiders are colored to blend in with their surroundings, giving them an advantage when hunting. Some of these spiders borrow a page from chameleons, gradually changing their colors to better blend with their surroundings -- a useful trait in a highly risky environment like the Everglades.

Fishing Spiders

Fishing spiders (Dolomedes triton) are large, dark-colored spiders that resemble wolf spiders. These spiders are unique in their ability to walk on the surface of water, even occasionally going after prey under the water. Their diet includes small fish, tadpoles, and insects that live near water. A typical hunting session for a fishing spider would take place at night. The spiders use the ability to sense vibrations through their legs. They hunt on water, but prefer to eat their kill on dry land. Although they spend time on and near water, fishing spiders also can be found in the plants and grasses near pools and streams. These provide cover from birds and other predators, and provide the spiders a place to spend their days and to consume their kills.

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