Other Types of Spiders
There are many other types of spiders all around us; in fact, it has been estimated that you are never more than 4 feet from a spider, indoors or outdoors! If you are having spider problems, call Regional Pest Management today at 1-800-5-STAR to arrange a thorough treatment.
Dolomedes is a genus of spiders of the family Pisauridae. They are also known as fishing spiders or dock spiders. Almost all Dolomedes species are semi-aquatic, with the exception of the tree-dwelling D. albineus in the southwestern United States and the grassland spider D. minor in New Zealand.
They capture prey by grappling with them using their foremost legs, which are tipped with small claws, and then injecting venom when they bite. Like all pisaurids, female Dolomedes carry their egg sacs in their chelicerae, and use silk to build a nursery web. These nursery webs are built shortly before the spiderlings emerge from the eggsac. The female places the egg sac in the nursery web, and the spiderlings emerge within twenty-four hours. The spiderlings of most North American Dolomedes species remain in the web for one week, and then disperse en masse.
D. triton, the six-spotted fishing spider, lives primarily in small lakes and ponds. This spider consumes mostly water striders, but like all Dolomedes, is an opportunistic ambush hunter that will eat anything that it can capture.
Other Dolomedes species include D. scriptus, the dark fishing spider (D. tenebrosus), the raft spider (D. fimbriatus) and the great raft spider D. plantarius.
The jumping spider family (Salticidae) contains more than 500 described genera and over 5,000 species, making it the largest family of spiders with about 13% of all species. Jumping spiders have good vision and use it for hunting and navigating. They are capable of jumping from place to place, secured by a silk tether. Both their book lungs and the tracheal system are well-developed, as they depend on both systems (bimodal breathing).
Jumping spiders are generally recognized by their eye pattern. They typically have eight eyes arranged in two or three rows. The front, and most distinctive row is enlarged and forward facing to enable stereoscopic vision. The others are situated back on the cephalothorax.
Colors and patterns vary widely. Several species of jumping spiders appear to mimic ants, beetles, or pseudoscorpions. Others may appear to be parts of grass stems, bumps on twigs, bark, part of a rock or even part of a sand surface.
Jumping spiders are generally diurnal, active hunters. Their well developed internal hydraulic system extends their limbs by altering the pressure of body fluid (blood) within them. This enables the spiders to jump without having large muscular legs like a grasshopper. The jumping spider can therefore jump 20 to 60 or even 75-80 times the length of their body. When a jumping spider is moving from place to place, and especially just before it jumps, it tethers a filament of silk to whatever it is standing on. Should it fall for one reason or another, it climbs back up the silk tether.
Unlike almost all other spiders, they can quite easily climb on glass. Minute hairs and claws on their feet enable them to grip imperfections in the glass. Jumping spiders also use their silk to weave small tent-like dwellings where females can protect their eggs, and which also serve as a shelter while moulting.
Jumping spiders are known for their curiosity. If approached by a human hand, instead of scuttling away to safety as most spiders do, the jumping spider will usually leap and turn to face the hand. Further approach may result in the spider jumping backwards while still eyeing the hand. The tiny creature will even raise its forelimbs and "hold its ground." Because of this contrast to other arachnids, the jumping spider is regarded as inquisitive as it is seemingly interested in whatever approaches it.
Crab spiders make up the Thomisidae family of the Araneae order. They are called crab spiders because they resemble crabs, with two front pairs of legs angled outward and bodies that are flattened and often angular. Also, like crabs, Thomisidae can move sideways or backward.
Crab spiders do not build webs to trap prey, but are hunters and ambushers. Some species sit on or among flowers, bark, fruit or leaves where they grab visiting insects. Individuals of some species, such as Misumena vatia, are able to change color between white and yellow to match the flower on which they're sitting. Other species, with their flattened bodies, hunt in the crevices of tree trunks or under loose bark. Members of the genus Xysticus hunt in the leaf litter on the ground. In each case, crab spiders use their powerful front legs to grab and hold onto prey while paralyzing it with a venomous bite.
The spiders of Thomisidae are not known to be harmful to humans. However, spiders of an unrelated genus, Sicarius, which are sometimes referred to as "crab spiders," are close cousins to the recluse spiders, and are highly venomous. The unrelated species Gasteracantha cancriformis is also commonly called the "crab spider."
Yellow Sac Spiders
The yellow (golden) sac spiders, genus Cheiracanthium, are members of the spider family Clubionidae (sac spiders): Members of this family build a sack-like, silken tube in foliage or under bark or stones as their lair. In nature Cheiracanthium species are usually found in foliage, but some species are found inside houses and around other human developments. These spiders are relatively small (10 mm body length), and are yellowish in color; they are difficult to distinguish from one another, and species identification requires examination by an arachnologist.
Yellow sac spiders are among the least known clinically significant spiders, but they are indeed capable of causing a painful bite with development of a necrotic lesion (not as severe as the brown recluse or hobo), and can sometimes produce systemic effects as well. They are very prone to bite defensively (more so than any other significantly venomous U.S. spider), and some bites in humans have occurred in unusual places, such as in automobiles and swimming pools. It is likely that many U.S. cases of necrotic arachnidism ascribed to the brown recluse spider outside of its natural range, are actually yellow sac spider bites.
Yellow sac spiders which have been implicted in human poisonings include C. inclusum in the United States and southwestern Canada, C. mildei in the United States, C. mordax in some parts of the United States and C. punctorium in Europe. In the United States inclusum (indigenous) and mildei (introduced) are the species most likely to be found, and the most likely to produce bites: These two spiders have a wide distribution in the United States, and precise ranges for them have not been defined. They tend to be transported easily, particularly in agricultural products such as grapes; in some areas it appears that grocery store grapes shipped from vineyards in California are a principal means of introduction.
Cheiracanthium mildei was first identified as a cause of necrotic arachnidism in 1970, when it was linked with skin lesions in the Boston, Massachusetts area (where it is the most common spider found in houses); it is also common in houses in New York City, and may well be the cause of recent "brown recluse bite" rumors circulating there. In the late 1970's and early 1980's mildei produced a significant number of bites in the Provo, Utah area. C. inclusum has been reported responsible for bites in Georgia and southwestern Canada; bites by this species are probably far more common and widespread than this however, and it is likely that more reports will surface as Cheiracanthium species become better known as clinically significant spiders.
Bites by yellow sac spiders generally produce instant, intense stinging pain, not unlike that of the sting of a wasp or hornet. This may be followed by localized redness, swelling and itching; these manifestations may or may not evolve into a necrotic lesion, but when that occurs healing is usually complete within eight weeks. Systemic effects are usually not severe, but when they occur may include chills, fever, headache, dizziness, nausea, anorexia, and sometimes shock. Treament for the local lesion should follow the same protocols as outlined for the hobo and brown recluse spiders: Likewise, corticosteroid therapy may be beneficial when systemic effects are present.
Cellar spiders (Pholcus phalangioides) live only in the safety of human homes: attics, cellars, garages and messy rooms where they can hang upside down in webs. Cellar spiders have gray-brown bodies that are about half an inch long. They have very long, skinny legs. Many times, cellar spiders are confused with Daddy Longlegs. Daddy Longlegs are really not spiders. Their bodies are oval shaped. A true spider's body has two parts.
Cellar spiders do not hurt people, but like all spiders, they are predators and carnivores. They will eat almost any kind of insect or bug. They will eat moths, mosquitoes, flies, or beetles that accidentally walk into the spider's web. The cellar spider will wrap an insect in a lot of spider silk and suck the bug dry. When the spider is finished, it will cut the insects loose, letting them fall to the ground making a pile of dead, dry, bug bodies.
Cellar spiders are good at finding secret places to live in. These spiders are not like most spiders who like to live alone. The cellar spider likes to live close to its mate. Male and female will often live next door to each other. The female will wrap her eggs in a see-through sack that she keeps in her mouth for safety. The babies will hatch after several weeks.
Enemies of the cellar spider are birds, wasps and people. Cellar spiders like to spin spider silk. The spider's legs are so thin that people can hardly tell the difference between the legs and the web. Cellar spiders will twist their bodies back and forth so fast that their bodies become blurred. This makes them hard to see. If they accidentally fall from the web, they run in a wobbly fashion, like a drunk, so that they cannot be seen easily.
Orb Weaver Spiders
The orb-weaver spiders (family Araneidae) are the builders of spiral wheel-shaped webs often found in gardens, fields and forests. Their common name is taken from the round shape of this typical web. Orb-weavers have eight similar eyes, legs hairy or spiny and no stridulating organs. The family is cosmopolitan, including many well-known large or brightly colored garden spiders. There are more than 2,800 species in over 160 genera worldwide, making this the third largest family of spiders known (behind Salticidae and Linyphiidae).
Generally, orb-weaving spiders are three-clawed builders of flat webs with sticky spiral capture silk. The building of a web is an engineering feat, begun when the spider floats a line on the wind to another surface. The spider secures the line and then drops another line from the center, making a "Y". The rest of the scaffolding follows with many radii of non-sticky silk being constructed before a final spiral of sticky capture silk. The third claw is used to walk on the non-sticky part of the web. Characteristically, the prey insect that blunders into the sticky lines is stunned by a quick bite and then wrapped in silk. If the prey is a venomous insect, such as a wasp, wrapping may precede biting.
Some "orb-weavers" do not build webs at all. Members of the genera Mastophora in the Americas, Cladomelea in Africa and Ordgarius in Australia produce sticky globules, which contain a pheromone analog. The globule is hung from a silken thread dangled by the spider from its front legs. The pheromone analog attracts male moths of only a few species. These get stuck on the globule and are reeled in to be eaten. Interestingly, both types of bolas spiders are highly camouflaged and difficult to locate.
The spiny orb-weaving spiders in the genera Gasteracantha and Micrathena look like plant seeds or thorns hanging in their orb-webs. Some species of Gasteracantha have very long horn-like spines protruding from their abdomens.
One feature of the webs of some orb-weavers is the stabilimentum, a crisscross band of silk through the center of the web. It is found in a number of genera, but Argiope, which includes the common garden spider of Europe as well as the yellow and banded garden spiders of North America, is a prime example. The band has been hypothesized to be a lure for prey, a marker to warn birds away from the web and a camouflage for the spider when it sits in the center of the web.
Most arachnid webs are vertical and the spiders usually hang with their head downward. A few webs, such as those of orb-weaver in the genus Metepiera have the orb hidden within a tangled space of web. Some Metepiera are semi-social and live in communal webs. In Mexico such communal webs have been cut out of trees or bushes and used for living fly paper.
Cobweb spider (Steatoda triangulosa) webs appear messy and disorganized, unlike the organized, circular webs made by orb-weavers and many other web-building spiders. In addition, cobweb spiders often have abdomens that are comparatively larger and more spherical than orb-weavers. Cobweb spiders have 8 eyes and (like all spiders), they have 8 legs, 2 body parts, and fang-like mouthparts called chelicerae.
Cobweb spiders undergo simple metamorphosis: like all spiders, young cobweb spiders hatch from eggs and look like tiny adults. They shed their skin as they grow. Most cobweb spiders live for less than 1 year. At the end of the summer, female cobweb spiders produce a large amount of eggs that they wrap in an egg sac made of silk. spiderlings hatch in the spring.
Cobweb spiders are common in North America, and can be found almost anywhere that they can find weeds, fences, trees, walls, or other upright structures to build their webs. Cobweb spiders are predators, and they will eat almost anything that is small enough to get trapped in their webs. Like most web-building spiders, cobweb spiders tend to have poor vision - they don't need to see very well because they can "feel" prey when it gets caught in their webs. Most cobweb spiders are considered beneficial to humans. They eat flies, mosquitoes, and other creatures. However, The black widow spider is a cobweb spider, and its bite can be dangerous.