Spiders

There are more than 30,000 kinds of spiders. Some are smaller than the head of a pin but some are larger than a person’s hand. Spiders are not insects, they are classified as arachnids. Spiders have eight legs but ants, bees, beetles and other insects have only six legs. Arachnids include daddy long legs, scorpions, mites and ticks. Spiders are most commonly brown, grey or black. A spider has no bones but its tough skin serves as a protective outer skeleton.

​

A spider’s body consists of the cephalothorax and the abdomen. Each of these sections has parts attached to it called appendages. A spider’s eyes are on top and near the front of its head. Different species have different numbers of eyes and the size and position also varies. Most species have eight eyes, arranged in two rows of four each. Hunting spiders have good eyesight at short distances and their eyesight allows them to form images of their prey and mates. Web-building spiders have poor eyesight and their eyes are used for detecting changes in light.

​

Below the spider’s eyes is its mouth opening. Spiders eat only liquids because they do not have chewing mouth parts. Around the mouth are various appendages which form a short ‘straw’ through which the spider sucks the body fluid of its victim. The spider can only eat some of the solid tissue of its prey by predigesting it. The spider sprays digestive juices on the tissue and the powerful juices dissolve the tissue.

A spider has four pairs of legs, which are attached to its cephalothorax and each leg has seven segments. In most kinds of spiders, the tip of the last segment has two or three claws. Surrounding the claws is a pad of hairs called the scopula. The scopula sticks to smooth surfaces and helps the spider walk on ceilings and walls. Spider’s legs are impervious to pesticides, thus making them difficult to control.

​

Each species of spider lives a different life. Many kinds of spiders live for only a year. Large wolf spiders live several years and some female tarantulas have lived for up to 20 years in captivity. Spiders become adults at different times of the year. Some mature in the fall and then mate and die during the winter. Others live through the winter, mate in the spring, and then die.

​

As soon as a male spider matures, it seeks a mate. The female spider may mistake the male for prey and eat him, but most male spiders perform courtship activities that identify themselves and attract the females. After mating, the female will lay her eggs several weeks or even months later. The number of eggs that a spider lays at one time varies with the size of the spider. An average sized female lays about 100 eggs but some of the largest spiders lay more than 2,000 eggs. The female wolf spider attaches the egg sac to her spinnerets, and drags it behind her and then carries the spider lings on her back after they have hatched. The most common types of spiders in this area are black widow spiders, wolf spiders, jumping spiders, garden spiders, crab spiders, funnel-web spiders and hobo spiders.

​

Spiders are generally good to have around, as they help minimize the population of harmful insects. The problem arises, however, when they negatively affect humans. The mere sight of a spider can be a real scare for some people. Aside from that, many spiders do bite humans and are poisonous, so it is a good idea to have a pest control company address your spider infestation.

​

Several spiders pose a serious threat to humans. The two that are the deadliest to humans are the Black Widow and the Brown Recluse. Since a few people die each year from the bite of either of these two spiders, it's extremely important for any person who is bitten by one of these spiders to seek treatment immediately. In some cases, hospitalization may be necessary.

​

Species of Spiders

There are numerous species of spider that can crop up around humans. In California the most common types are:​

​

• Black Widow : Genus Latrodectus
  Appearance: Female is 1/2 inch long; shiny black, with hourglass-shaped red mark on underside of abdomen.
  Habits: Can be found almost anywhere, indoors or out; prefer to build their nests close to the ground.
  Diet: Insects trapped in web made by female.
  Reproduction: Contrary to popular belief, female is usually unsuccessful in any attempt to eat male after mating; 300 to 400 eggs are laid in silken cocoon, hatch in about ten days.
  Other Information: Black widows are not aggressive, and will not bite unless provoked; bites are poisonous, but rarely fatal. This spider is found outdoors in all kinds of protected areas. Around homes, it lives in garages, cellars, furniture, ventilators, rain spouts, gas and electric meters and many other undisturbed places. Like most spiders, the black widow is shy and retiring. People are bitten when they accidentally disturb a hidden spider or its web. Females are usually jet black in color. The lower side of their rounded abdomen is marked by two reddish triangles resembling an hourglass in shape. In some individuals the markings may be irregular, spot-like or even absent. The black widow’s overall length averages about 1 ½ inches. The black widow has eight eyes in two rows, which is a common pattern in many spiders. Gravid females lay their eggs singly in a loosely woven cup of silk. The oval egg sacs are about ½ inch long. These egg sacs hold from 25 to 900 or more eggs, which undergo an incubation period of about 20 days. The spiderling’s usually stay near the egg sac for a few days after they emerge. Cannibalism is prevalent during this time. Eventually the surviving spiderling’s disperse by means of small silk threads. When they are about one-third grown they establish themselves in some protected place and construct loosely woven webs. The spiders usually remain in their webs for the rest of their lives. As they mature they extend their webs and capture progressively larger prey. Males eventually leave their webs to find females for mating. The females sometimes eat the males after mating; this habit is what gave the black widow their name. A black widow bite feels like a pin prick and sometimes is not even felt. Usually, a slight local swelling and two red spots surrounded by local redness indicates the location of the bite. Pain becomes intense in 1 to 3 hours and may continue for up to 48 hours. Symptoms include abdominal pains, rise in blood tremors, loss of muscle tone and vomiting. The toxin also causes breathing difficulties and sometimes unconsciousness. Mortality estimates from a black widow spider bite is less than 5 percent.

​

• Brown Recluse Spider: Loxosceles reclusa
  Appearance: Yellowish to brown, with a dark brown violin-shaped dorsal marking; 5/8 to 1/2 inch long.
  Habits: Can be found outside under rocks, leaves, debris, bark, woodpiles, utility boxes; found inside in storage areas such as closets, attics, bedrooms; usually found close to the ground.
  Diet: Cockroaches, crickets and other soft-bodied insects.
  Reproduction: Mating occurs from Feb. to Oct.; 40 to 50 eggs are deposited in off-white, round silken cases; lifetime averages from one to two years.
  Other Information: Bites when disturbed; bites can cause a disfiguring scar. The brown recluse spider inhabits many southern and Midwest states, and it often lives around human dwellings. Brown recluse spiders are found in bathrooms, closets, under and around furniture, behind baseboards, door facings, corners and crevices along with many other protected areas. They also like cluttered cellars and garages and are most active at night. Many of the bites people have received from this spider are when they entrap the spider, such as rolling over on it when they sleep, or placing on a piece of clothing that has been undisturbed for a long period of time. The brown recluse spider is a non aggressive spider that spins a white or grayish, nondescript web. Its body and legs together cover about the same area as a quarter or half dollar, and the body is only about ¼ to ½ inch long. The coloring of the recluse varies from an orange-yellow to dark brown or almost black. The most distinguishing characteristics are the spider’s eyes and back markings. It has six eyes in three pairs arranged in a semicircle on the forepart of the head. This eye pattern is uncommon in spiders and will help eliminate many species suspected to be brown recluse spiders. The eyes also form the base of a violin-shaped marking on the back. The neck of the “violin” is formed by a distinct, short, median groove. The effects of a brown recluse spider bite may be immediate or delayed, depending upon the amount of venom injected and the victim’s sensitivity. The bite usually causes a stinging sensation and then intense pain. Within 24 to 36 hours a systemic reaction may occur, characterized by restlessness, fever, chills, nausea, weakness and joint pain. The bite also produces a small blister surrounded by a large congested and swollen area. The venom usually kills the affected tissue, which gradually sloughs away and exposes underlying tissues. The edges around the wound will thicken, while the exposed center fills with dense scar tissue. Healing may take 6 to 8 weeks, leaving scars of various sizes.

​

• Black House Spider(BADUMNA INSIGNIS)

Appearance -This species is a robust spider, 1-1.5cm in body length.Carapace and legs are dark brown to black and the abdomen is charcoal grey. The dorsal pattern of white marking is sometimes indistinct.

​

LifecycleThe female constructs several white silk eggs sacs, which are secured within the web retreat. The female stays with the eggs until they hatch. The spider lings then disperse. The spiders mature during the summertime and live for about two years.

​

Habits

• Black house spider webs form untidy, lacy sheets with funnel like entrances. They are found on tree trunks, logs, rock walls, and buildings (also in window frames and crevices).

• Commonly also found in urban areas, Black House Spiders also build webs in dark corners of windows, veranda’s, sheds of fences.

• The female spider never leaves her web unless forced to, but keeps on repairing it – old webs can look grey and woolly from the constant additions of silk.

• Poisonous but no fatalities.

​

Common House Spider(Family Diaspidae)

Appearance: Adult – body length excluding legs 1/4" – 3/8". Yellow brown body with faint markings. Abdomen pale grey brown with short hairs.

​

Lifecycle

The egg sac produced by the female is spherical, covered with a layer of silk and placed within the web structure. The male will mate several times with the female before dying. Adults may live for several years.

 

Habits

• Found in buildings, sheds and walls.

• This spider produces a sheet web.

• Daddy Long Legs Spider

​

​

​

​