Hobo Integrated Pest Management in and Around the Home

The , agrestis, is a members of the California medical com- European immigrant that has only been munity have read about the hobo spider implicated as a potentially poisonous and the effects of its venom and have spider in the United States since the started to diagnose hobo spider bites 1980s (Fig. 1). Another name commonly without proof of the spider. The pur- used for this spider is the aggressive pose of this Pest Note is to offer current house spider (although this spider is information on the status of the hobo not aggressive). However, in seeking spider in California. name stability, the American Arach- nological Society has chosen “hobo IDENTIFICATION spider” as the spider’s official common The hobo spider is a member of the name. The name “hobo” is linked to the spider family , a common spider’s presumed spread to distant group that has many species through- cities via the railways. out California and the United States. Agelenid can have very dense The hobo spider does not live in Cali- populations in certain habitats. The fornia and has never been documented members of this family construct a Figure 1. The hobo spider, Tegenaria in the state. There are many cases, how- snare referred to as a funnel web, which agrestis, does not live in California. ever, of common related spiders being is a trampolinelike, horizontal web con- misidentified as hobo spiders by the stricting back into a funnel or hole (Fig. as a possibility. None of these species general public and even by pest control 2). The web is typically found in a crack causes necrotic wounds or serious in- operators. In North America, this spider between bricks or under wood, stones, jury to humans. lives in the Pacific Northwest from or vegetation. The spider waits in the British Columbia east to Montana, Wyo- mouth of the funnel for prey to fall To distinguish funnel-weaving spider ming and Colorado and south through onto the horizontal surface, and then it species, the ’s reproductive Oregon and northern Utah, so it is rushes out, grabs the prey, and takes it structures must be examined, a task conceivable that its range may extend back to its funnel to consume. If you go that requires the skills of a qualified into the northernmost areas of Cali- outside on a dewy morning, you can arachnologist. Each spider species has fornia. However, there have been no often see many of these funnel webs. documented verifications by a qualified a distinctive “lock and key” design of the male and female reproductive or- arachnologist (spider specialist) to date. The hobo spider shares traits with gans. Through evolution, the physical many of its relatives in the Agelenidae features of the males and females have Although once common in Seattle, the family, including coloration and web- become unique for each species and hobo spider apparently is being com- building characteristics. It is a brown hence are used by arachnologists for petitively displaced by another Euro- spider about 1/4 to 5/8 inch in body pean Tegenaria (TEJ-in-Er-ee-uh) species length and lives in a funnel web. There so that it is now difficult (but not im- are dozens of similar looking spider possible) to find hobo spiders in Seattle. species in California that build funnel Hobo spiders are more common further webs, including members of the genera east and are easily found around Salt (2 species), Calilena (13 spe- Lake City, Utah. Interest in this spider cies), Hololena (21 species), Novalena (4 has been growing in California because species), and Rualena (8 species). There it supposedly causes necrotic (rotting is even a unique , flesh) wounds similar to brown recluse Sosippus (1 species), in California that, bites, another spider that does not oc- unlike its free-hunting relatives, builds cur in California. (For more information a funnel web. Therefore, if you see on the brown recluse, see Pest Notes: a funnel web in California, there are Brown Recluse and Other Recluse Spiders, Figure 1. Funnel web of an agelenid many other spiders you should suspect spider between bricks in a wall. Note listed in “Suggested Reading.”) Some before even considering the hobo spider hole at top, where spider often waits.

EST OTES Publication 7488 PUniversity of CaliforniaN Agriculture and Natural Resources revised May 2006 May 2006 Hobo Spider

species differentiation. Until someone carapace has examined reproductive features abdomen on dozens of hobo spiders and also re- eyes lated species, it is unlikely that a hobo chelicera spider would be correctly identified pedipalp with the naked eye. Therefore, virtu- spinnerets ally any “hobo spider” identification by a non-arachnologist in California should be suspect.

If you have access to a magnifying device (hand lens, microscope, etc.), there is an easy way to determine if the carapace spider you have IS NOT a hobo spider. eyes First, the spider must be associated with a funnel web; otherwise it could easily be one of the hundreds of other non-agelenid spider species in Califor- nia. All funnel-weaving spiders have chelicera eight eyes arranged in two rows. If you look at the spider head on, however, a b most of the agelenid spiders in Califor- nia have their two rows of eyes curved Figure 2. (Top) Side view of spider body. Closeups show face of (a) an agelenid spi- so strongly that it appears that their der, , with eyes in three rows; and (b) the hobo spider, Tegenaria eyes are actually in three horizontal agrestis, with eyes in two rows. rows with four eyes in the middle row with two eyes above and two eyes be- low this row (Fig. 3a). This is known as to humans even though they are closely bites and found that there is only one the 2-4-2 eye pattern. Exceptions are the related to the hobo spider. case of a verified bite by a hobo spider spiders of the genus Tegenaria, which that resulted in a necrotic skin lesion have eyes that are in the more common MEDICAL ASPECTS and this was in a person who had a pattern of two rows of four (Fig. 3b). Hobo spiders have been reported to pre-existing medical condition that also This is also the most common eye pat- have a bite that can leave a necrotic (i.e., leads to necrotic skin lesions. Most of tern for spiders in general, and unless rotting flesh) wound that progresses the basis for blaming the hobo spider you remove the spider from a funnel over several days—similar to that is based on extrapolation from venom web, it will probably not be a funnel- caused by a brown recluse bite. Another experiments with rabbits. As impor- weaving spider. reported characteristic symptom of tant as these experiments are, one must hobo spider bites is a headache that per- keep in mind that there are differences Nonetheless, it is not uncommon to sists for 2 to 7 days and does not abate in response to spider venoms. find a funnel-weaving spider with two with analgesics (pain relievers). As an example, straight rows of eyes in California. venom causes skin lesions in humans, There are two species of Tegenaria in the In its native European habitat, the hobo rabbits, and guinea pigs, but not mice state, T. pagana and T. domestica. Neither spider venom is not considered poi- or rats; Australian funnel web spiders species is native to the United States. sonous to humans. A research study are highly toxic to primates but not Their coloration is similar enough to (still unpublished) was undertaken to other mammals. Therefore, until a that of the hobo spider, T. agrestis, that compare hobo spider venom from both study is done with a series of verified anyone except a spider expert might Pacific Northwest and European hobo bites of hobo spiders in humans result- confuse them with the hobo spider. spider populations. The venom from ing in skin lesions, it is more sensible to Tegenaria pagana is found in coastal Cali- both populations was injected into the question the potential of hobo spider to fornia regions to slightly inland. Tege- same strain of rabbits used in the initial cause skin lesions rather than to make naria domestica, however, is an extremely research that implicated hobo spiders the mistake of emphatically stating that common spider, about 1/4 to 1/2 inch in as potentially poisonous to humans. it is a dangerous spider. The definitive body length, found throughout Califor- Neither venom in the study produced proof is still lacking. nia often inside homes, as is evident by necrotic wounds in the rabbits. the name “domestica.” In fact, T. domes- If you do get a necrotic wound in Cali- tica is found throughout the world, hav- Additionally, an editorial in the Annals fornia, you and your medical profes- ing been carried by commerce. Neither of Emergency Medicine in 2004 examined sional should consider many other of these spiders is considered poisonous the medical literature on hobo spider common causes to be much more prob-

◆  of 4 ◆ May 2006 Hobo Spider able than a bite from a hobo or brown when it is lifted up. If you plan to send recluse spider. If an is in- Also available online, http://pep.wsu. the spider to an expert for identification, volved at all, one should first consider edu/pdf/PLS116_1.pdf. try to keep it in an undamaged condi- all those creatures that seek out mam- tion because a crushed specimen may mals for blood meals and may cause Vetter, R. S. and G. K. Isbister. 2004. be difficult to identify. necrotic-type wounds. These include Do hobo spider bites cause dermone- crotic injuries? Ann. Emerg. Medicine mites, fleas, bed bugs, soft ticks, hard Suggested Reading ticks, conenose bugs, and kissing bugs 44:605-607. Binford, G. J. 2001. An analysis of (see Pest Notes on Fleas, Bed Bugs, Cone- geographic and intersexual chemi- nose Bugs, and Lyme Disease in California Vetter, R. S., A. H. Roe, R. G. Bennett, cal variation in venoms of the spider listed in the “Suggested Reading”). In C. R. Baird, L. A. Royce, W. T. Lanier, Tegenaria agrestis (Agelenidae). addition there is a long list of medical A. L. Antonelli and P. E. Cushing. 2003. Toxicon. 39:955-968. conditions and diseases that exhibit Distribution of the medically-implicated necrotic-type wounds. A few of these hobo spider (Araneae: Agelenidae) and Crawford, R., and D. K. Vest. 1989. The are Staphylococcus and Streptococcus its harmless congener, Tegenaria duellica, hobo spider and other European house spi- bacterial infections; lymphomatoid in the United States and Canada. J. Med. ders. Burke Museum Educ. Bulletin No. 1. v papulosis (a non-Hodgkin’s disease Entomol. 40:159-164. lymphoma); diabetic ulcer; pyoderma Greenberg, L., and J. H. Klotz. Sept gangrenosum; infected herpes simplex; 2002. Pest Notes: Bed Bugs. Oakland: herpes zoster (“shingles”); and Lyme Univ. Calif. Agric. Nat. Res. Publ. 7454. disease. Any and all of these situations Also available online, http://www.ipm. are more likely than the bite of a hobo ucdavis.edu. spider in California. Greenberg, L., and J. H. Klotz. Nov MANAGEMENT 2002. Pest Notes: Conenose Bugs. Oak- Because the hobo spider is not known land: Univ. Calif. Agric. Nat. Res. Publ. to live in California, there is no need for 7455. Also available online, http:// control. However, reducing trash and www.ipm.ucdavis.edu. rubble around the house and sealing windows and door jams will help to Lane, R. S. Dec 2000. Pest Notes: Lyme reduce the numbers of most spiders and Disease in California. Oakland: Univ. other that can gain access Calif. Agric. Nat. Res. Publ. 7485. Also into the home. In the garage (a well- available online, http://www.ipm. known haven for spiders), use plastic ucdavis.edu. bags tightly closed to store all garden- ing apparel (gloves, old shirts, boots) UC Statewide IPM Program. Nov 2000. and sports gear (baseball mitts, roller Pest Notes: Fleas. Oakland: Univ. Calif. skates) that is used only sporadically. Agric. Nat. Res. Publ. 7419. Also avail- Remember that this will minimize en- able online, http://www.ipm.ucdavis.edu. counters with spiders, but not eliminate them completely. Vetter, R. S. In press 2006. Pest Notes: Brown Recluse and Other Recluse Spi- Typically, pesticide control of spiders ders. Oakland: Univ. Calif. Agric. Nat. is difficult unless you actually see the Res. Publ. 7468. Also available online, spider and are able to spray it. There are http://www.ipm.ucdavis.edu. various insecticides available in retail outlets labeled for spider control. It is Vetter, R. S. 2000. Myth: Idiopathic just as easy and much less toxic to crush wounds are often due to brown recluse the spider with a rolled up newspaper or other spider bites throughout the or your shoe. Sticky traps placed along United States. Western Journal of Medi- floorboards out of the reach of pets and cine 173:357-358. Also available online, young children offer a noninsecticidal http://spiders.ucr.edu. way to trap spiders as well as provide an idea of population levels in the struc- Vetter, R. and A. Antonelli. 2002. How ture. You can also remove a spider from to identify (and misidentify) a hobo spider. your home by placing a jar over it and Washington State University Coopera- slipping a piece of paper under the jar tive Extension Pest Leaflet Series #116. that then seals off the opening of the jar

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For more information contact the University of California Cooperative Extension in your county. See your telephone directory for addresses and phone numbers.

AUTHOR: R. S. Vetter, Entomology, UC Riverside TECHNICAL EDITOR: M. L. Flint DESIGN AND PRODUCTION: P. N. Galin ILLUSTRATIONS: Fig. 1: Drawing by Margaret Davidson, reprinted by permission of the Burke Museum of Natural History & Culture, Univ. of Washington ©1983. No part of this illustration may be used or reproduced in any manner without the written permission of the Burke Museum; Fig. 2: R. S. Vetter; Fig. 3 (top): Spiders in San Joaquin Val- ley Grape Vineyards. 1995. UC ANR Publ. 21530; Fig. 3 (closeups a & b): R. S. Vetter

Produced by IPM Education & Publications, UC Statewide IPM Program, University of WARNING ON THE USE OF CHEMICALS California, Davis, CA 95616-8620 Pesticides are poisonous. Always read and carefully follow all precautions and safety recommendations given on the container label. Store all chemicals in the original labeled containers in a locked cabinet or shed, This Pest Note is available on the away from food or feeds, and out of the reach of children, unauthorized persons, pets, and livestock. World Wide Web (www.ipm.ucdavis.edu) Confine chemicals to the property being treated. Avoid drift onto neighboring properties, especially gardens containing fruits or vegetables ready to be picked. Do not place containers containing pesticide in the trash or pour pesticides down sink or toilet. Either use the pesticide according to the label or take unwanted pesticides to a Household Hazardous Waste Collection site. Contact your county agricultural commissioner for additional information on safe container disposal and for the location of the Household Hazardous Waste Collection site nearest you. Dispose of empty containers by following label directions. Never reuse or burn the containers or dispose of them in such a manner that they may contaminate water supplies or natural waterways. This publication has been anonymously peer reviewed for technical accuracy by University of California scientists and other qualified profession- The University of California prohibits discrimination or harassment of any person on the basis of race, als. This review process was managed by the ANR color, national origin, religion, sex, gender identity, pregnancy (including childbirth, and medical condi- Associate Editor for Pest Management. tions related to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related To simplify information, trade names of products or genetic characteristics), ancestry, marital status, age, sexual orientation, citizenship, or status as a have been used. No endorsement of named products covered veteran (covered veterans are special disabled veterans, recently separated veterans, Vietnam is intended, nor is criticism implied of similar products era veterans, or any other veterans who served on active duty during a war or in a campaign or expedition that are not mentioned. for which a campaign badge has been authorized) in any of its programs or activities. University policy is This material is partially based upon work supported intended to be consistent with the provisions of applicable State and Federal laws. Inquiries regarding the by the Extension Service, U.S. Department of University’s nondiscrimination policies may be directed to the Affirmative Action/Staff Personnel Services Agriculture, under special project Section 3(d), Director, University of California, Agriculture and Natural Resources, 300 Lakeside Drive, 6th Floor, Oak- Integrated Pest Management. land, CA 94612-3550, (510) 987-0096.

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