Florida Insects: Spiders | |
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Spiders belong to the class Arachnida, which contains
organisms with four pairs of legs, no antennae and two body regions. A
shield-like carapace covers the head and the area from which the legs arise.
Their mouthparts, or chelicerae, function vertically. Crab Spiders- 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- 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- 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- 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-Weavers- 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. |
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