Spiders | Southern California – Cal Coast Termite & Pest, Inc.

Spiders

Many people fear or dislike spiders, but, for the most part, spiders are beneficial because of their role as predators of insects and other arthropods, and most cannot harm people. Spiders that might injure people—for example, black widows—generally spend most of their time hidden under furniture or boxes, or in woodpiles, corners, or crevices. The spiders commonly seen out in the open during the day are unlikely to bite people.

Brown Recluse

The Brown Recluse, notorious for poisonous bites, is not a common species in California. There are no populations of the brown recluse in the state, and fewer than 20 verified specimens have been collected over several decades in California. Yet in California, people frequently relate stories in which they or someone they know was supposedly bitten or they have had a physician diagnose them with a brown recluse spider bite. 
However, there are several other species of recluse spiders that can occur in southern areas of California, and that can cause similar medical concerns.

Identification

The most definitive physical feature of recluse spiders is their eyes: most spiders have eight eyes that are typically arranged in two rows of four, but recluse spiders have six equal-sized eyes arranged in three pairs, called dyads. There is a dyad at the front of the cephalothorax (the first main body part to which the legs attach) and another dyad on each side further back, with a space separating the dyads from one another.
Some other spiders share each of these physical characteristics. However, to be identified as a recluse spider, it must have all five of these characteristics.

Six eyes in dyads (pairs).
Uniformly colored abdomen with fine hairs.
No spines on the legs.
Uniformly colored legs.
Body not more than 3/8″ in length.

Spider Identification

Spiders resemble insects and sometimes are confused with them, but they are arachnids, not insects. Spiders have eight legs and two body parts—a head region and an abdomen. They lack wings and antennae. Although spiders often are found on plants, they eat mainly insects, other spiders, and related arthropods, not plants. Most spiders have toxic venom, which they use to kill their prey. However, only those spiders whose venom typically causes a serious reaction in humans are called “poisonous” spiders.

Common Spider Families in North America

Funnel Weavers or Grass Spiders

Grass spiders sit-and-wait predators feed during the day and night on the ground in most types of vegetation, including low-growing plants and trees. Spin funnel-shaped webs, often with several-inch-wide, flat extensions covering plants or soil. The spider waits in the hole of its web. When it detects vibrations from an insect that flew or walked into the web, the spider runs out, captures and bites the prey, then carries it back into the funnel to be eaten. 
Webs on low vegetation become conspicuous in morning light after collecting dew. Funnel weavers have six or eight eyes, all about the same size, arranged in two rows. There are about 300 species in North America.

Orb Weavers or Garden Spiders

Garden spiders feed on insects that fly, fall, or are blown into the web. Elaborate silken webs are spun in concentric circles. Spiderlings often make symmetrical webs; mature spiders may spin a more specialized design that is helpful in identifying certain species. The spider rests at the center of its web or hides in a shelter near the edge, waiting for prey to become entangled. Orb weavers generally have poor vision and rely on web vibrations to locate and identify prey. There are about 200 species in North America.

Sac Spiders or Two-Clawed Hunting Spiders

Two-clawed hunting spiders Stalk and capture prey that is walking or resting on surfaces. They spin silken tubes or sacs under bark, among leaves, and in low plants or on the ground, where they hide during the day or retreat after hunting. They are commonly nocturnal, medium-sized, pale spiders with few markings. There are about 200 species in North America.

Dwarf Spiders

Dwarf spiders prey on insects that fall, walk, or land in their web. Diurnal (day-active) spiders occur in the plant canopy and among litter on the ground. They produce sheetlike webs on the surface of plants or soil and are common in some field and vegetable crops. Most are relatively small. There are several hundred species in North America.

Wolf Spiders

Wolf spiders prey on insects that are walking or resting on the ground. Actively hunt in the open during the day and night, often observed on the ground in litter and on low vegetation. It can occur in burrows and under debris in the soil. Instead of spinning webs to catch prey, they make a small, thick web where they rest. Have a distinctive pattern of eyes: four small eyes in front in a straight row, one middle pair of larger eyes, and one rear pair of widely spaced eyes on top of the head. 
They have long, hairy legs. They are usually black and white or strongly contrasting light and dark, which can make them difficult to discern unless they are moving. There are about 200 species in North America.

Lynx Spiders

Lynx spiders stalk and capture resting or walking insects. They are active hunters with good vision. Most have spiny legs and a brightly colored body that tapers sharply toward the rear. They have four pairs of eyes grouped in a hexagon. There are about 2 dozen known species in North America.

Jumping Spiders

Jumping spiders are day-active hunters in plants or on the ground. They make no web; instead, they stalk and pounce on prey by jumping distances many times their body length. Jumping spiders have a distinctive pattern of eyes in three rows: the first row of four eyes, with large and distinctive middle eyes; a second row of two very small to minute eyes; and a third row of two medium-sized eyes. 
They usually have an iridescent, metallic-colored abdomen and a black carapace. There are about 300 species in North America.

Cobweb Weaver or Comb-Footed Spiders

Cobweb weavers feed on insects that walk or fly into their webs. Almost always found hanging upside down by their claws in irregularly spun, sticky webs, waiting for prey. The spider is usually concealed in a corner of the web, in a silken tent, or behind debris. This group includes the black widow spider, which produces relatively thick silk that feels rough and sticky. They generally have a soft, round, bulbous abdomen and slender legs without spines. There are over 200 species in North America.

Crab Spiders or Flower Spiders

Crab spiders stalk and capture insects walking or resting on surfaces. Diurnal hunters that do not spin webs. The front two pairs of legs are enlarged and extend beyond the side of their flattened body, making them look like tiny crabs. Their small eyes occur in two slightly curved rows, with the top row often much wider than the lower row. There are over 200 species in North America.