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Spiders
Latin Name: Tegenaria domestica
Common Name: Barn Funnel Weaver
Other Names: Domestic house spider (European name)
Pest Details
Origin:
Possibly European in origin, but current thought is that it may be native to Canada and has spread south from there. It now is found throughout much of the U.S. and southern Canada as well as all of Europe.
Biology:
As do other funnel weaver spiders these are hunting spiders that are quite agile and run well. However, they spin large webs over surfaces, particularly on low, dense plants outdoors, and reside within a narrow tube or “funnel” below that webbing. When an insect is detected on the webbing above it is quickly grabbed, subdued, and eaten. These spiders may often create their webs indoors where clutter is found in undisturbed places. Indoors they may live up to 2 years but outdoors will die once cold weather occurs in the winter. In the fall the female creates her egg
Latin Name: Latrodectus mactans, L. hesperus
Common Name: Black Widow Spiders
Latin Family Name: Theridiidae
Other Names: Southern Black Widow Spider, Western Black Widow Spider
Pest Details
Origin:
Five species of these native spiders occur in North America, being found in all states and in southern Canada. Other species may be found worldwide.
Biology:
The black widow spiders are the most dangerous spiders with respect to human health in the U.S. They are one of the few spiders capable of biting humans that inject a neurotoxin, and the effect of the bite can be serious and potentially fatal. Only females bite humans, but both males and females construct webs to capture other prey, primarily flying insects. Males also enter a female’s web for mating, and if the female is not receptive the male may be eaten. The life span of black widow females averages around 180 days as an adult, taking about
Latin Name: Loxosceles reclusa
Common Name: Brown Recluse Spider
Latin Family Name: Loxoscelidae
Other Names: Violin spider, Fiddleback spider
Pest Details
Origin:
There are 11 species of Loxosceles that are native to the United States, and at least one imported species that is found in the southwest. The Brown Recluse, L. reclusa, has the widest range, from a small area of western Florida to Texas and north to Iowa. It has been found sporadically as a transient in other states. The other 10 native species are found in the southwest from Texas to California.
Biology:
The Brown Recluse, Loxosceles reclusa, has a reputation that far exceeds reality. It is a hunting spider that uses it web only for lining its retreat and for covering its eggs. It is very capable of biting humans, and the venom is a cyto-toxic venom which causes tissue death at the site of the bite, possibly leading to a large, infected, and lingering
Latin Name: Latrodectus geometricus
Common Name: Brown Widow Spider
Other Names: N/A
Pest Details
Origin:
The actual origin of this species is uncertain, as it was first discovered in South America, but believed to have originated in Africa. It was found in Florida in the mid-20th century and remained restricted to that state until around 2000 when it began to be found in other states from Texas to South Carolina and in 2003 showed up in southern California. Since that time it has spread rapidly throughout southern California and is thought to even be displacing the black widows there.
Biology:
This imported widow spider is still misunderstood. Some experts claim its venom is far more potent than that of black widows while others claim it is less potent. Yet other experts claim that the bite is less dramatic than that of black widows because the brown widow injects less venom and the venom tends to affect only
Latin Name: Pholcidae
Common Name: Cellar Spiders
Latin Family Name: Pholcidae
Other Names: Daddy Longlegs
Pest Details
Origin:
Several dozen species of Pholcids are native to North America, with the three species listed above the most common to be found in and on structures.
Biology:
The cellar spiders are often called “Daddy Long-legs” due to their very long, thin legs. However, the true Daddy Long-legs is another animal entirely, called the Harvestman. The cellar spiders are incapable of biting humans and are harmless to us and our pets. Their primary crime is the messiness of their webs, which are thin and flimsy but tend to gather dust and floating debris, as well as the remains of the insects the spiders have fed on. Webs typically appear under the eaves of roofs, around porch lights, within garages, and indoors around windows where the light may draw small insects that the spiders feed on. Their
Latin Name: Loxosceles laeta
Common Name: Chilean Recluse Spider
Other Names: Brown spiders, Fiddleback spiders
Pest Details
Origin:
This species is native to much of South America, but commonly hitchhikes on exported materials. It has been found in several Central America countries, in Finland, and in scattered states in the U.S., including California, Florida, Massachusetts, and Kansas. It does not appear currently to be a breeding resident in North America.
Biology:
This is one of the largest of the Loxosceles species, with a body length of around 5/8 inch. It is not a resident spider in the U.S. as far as is known, but has been discovered a number of times, associated with imported materials from South America. Females create an egg sac and deposit up to 50 eggs in it, with a potential to create 5 egg batches in one year. Development from egg to adult requires about 1 year and they can live for up to 7 years. They are
Latin Name: Tegenaria gigantea
Common Name: Giant House Spider
Other Names: Greater European house spider
Pest Details
Origin:
This species currently is believed to be native to Europe but was first discovered in North America in 1929, reaching Seattle in 1960.
Biology:
This is a third species in this genus that is found in the Pacific Northwest, with a much more restricted range than T. agrestis or T. domestica. It can be found along the coastal areas from B.C. south into northern Oregon. It appears to out-compete the Hobo spider as homes in Seattle that previously were well stocked with Hobo spiders in the 1960’s were instead occupied primarily by T. gigantea by the 1980’s. It is commonly found both indoors and outdoors but is nocturnal, hiding during the daytime beneath materials on floors or on the ground and hunting at night.
Identification:
Despite its common name this is not a particularly large spider, with females
Latin Name: Gnaphosa sp.
Common Name: Ground Spiders
Other Names: House Spider
Pest Details
Origin:
These are primarily native species in North America.
Biology:
This family of spiders contains many species in a number of genera, with the genus Gnaphosa one of the largest with over 20 species. These common spiders are medium in size but very fast running and commonly enter structures during or following their nocturnal activities. Because of their obvious presence and rapid movements they are a concern to homeowners. While they are capable of biting their venom is considered to be of no consequence to humans. They hide during the day under any available materials on the ground or floors, often resting within a silk tube that they have constructed.
Identification:
Adult spiders are medium in size with a body length of about ½ inch. Their color ranges from black cephalothorax and dark gray abdomen to reddish orange
Latin Name: Tegenaria agrestis
Common Name: Hobo Spider
Latin Family Name: Agelenidae
Other Names: Aggressive house spider
Pest Details
Origin:
Like the Domestic house spider this species was believed to be native to Europe, but new evidence suggests that it has long been a native of western Canada and now has moved into the Pacific Northwest of the U.S. as well, where it is common in and around homes. It appears to be moving eastward and now can be found in Colorado, Montana, and Wyoming and west to the Pacific Coast of Oregon, Washington, and British Columbia.
Biology:
This species of funnel weaver has suffered from some terrible misconceptions, the first being that its Latin name of “agrestis” means “aggressive”. It does not, and instead agrestis is Latin for “rural”, meaning it is found most often in fields. It is a very NON-aggressive spider that prefers to retreat from threats and hide from human activity.
Latin Name: Herpyllus ecclesiasticus
Common Name: Parson Spider
Latin Family Name: Gnaphosidae
Other Names: N/A
Pest Details
Origin:
Native to North America, and found throughout the United States.
Biology:
These are hunting spiders which use their silk only for lining their retreat and for creating their egg sacs. They may be very fast moving spiders and commonly enter structures to hunt for food or harborage. They are primarily nocturnal, but when found in structures may be seen walking along floors, countertops, walls, or ceilings. They are capable of biting humans, but their venom is generally not considered dangerous. The venom is a cyto-toxic venom, and may cause death of the tissues at the site of the bite, potentially leading to an open wound.
Identification:
The Parson Spider is a medium sized spider with dark brown legs and body sections. The cephalothorax is narrower at the front than at the