Featured Research

from universities, journals, and other organizations

Are brown widows displacing black widow spiders around southern California homes?

Date:
July 2, 2012
Source:
Entomological Society of America
Summary:
Brown widow spiders are relatively new to North America, where they were first documented in Florida in 1935, and even newer to southern California, where they were only recently discovered in 2003. However, in the last decade they've been so successful that they may be displacing native black widow spiders. If so, the overall danger to homeowners may decrease because brown widow spider bites are less toxic than those of native western black widow spiders.

Black widow spider.
Credit: BVDC / Fotolia

Brown widow spiders are relatively new to North America, where they were first documented in Florida in 1935, and even newer to southern California, where they were only recently discovered in 2003. However, in the last decade they have been so successful that they may be displacing native black widow spiders. If so, the overall danger to homeowners may decrease because brown widow spider bites are less toxic than those of native western black widow spiders.

In "The Prevalence of Brown Widow and Black Widow Spiders (Araneae: Theridiidae) in Urban Southern California," a soon-to-be-released article in the July issue of the Journal of Medical Entomology, the authors describe the results of their efforts to document the presence of brown widows in southern California by performing timed searches in various habitats, such as urban properties, agricultural lands, developed parks, and undeveloped natural areas. They also included the native western black widow spider to compare the abundance and habitat selection of the two species.

"The brown widows really burst on to the scene in a very short time, and we found brown widows in many habitats where we expected to find black widows," said corresponding author Richard Vetter (University of California, Riverside). "There may be some competition where brown widows are displacing black widows because there is some habitat overlap. There are also places where only brown widows were able to make homes, but in other habitats the black widows still predominate."

After collecting data at 72 sites, which involved 96.8 hours of collecting, the authors found 20 times as many brown widows than black widows outside homes, especially under outdoor tables and chairs, and in tiny spaces in walls, fences and other objects. Neither spider is found in the living space of houses.

"Homeowners would benefit to know about the hiding places of brown widows, displaying care when placing their hands in nooks and crannies," the authors conclude. However, they should also keep in mind that even if the chances of being bitten do increase, the dangers are lessened because the brown widow bite is less toxic than that of the black widow.


Story Source:

The above story is based on materials provided by Entomological Society of America. Note: Materials may be edited for content and length.


Journal Reference:

  1. Vetter, Richard S.; Vincent, Leonard S.; Danielsen, Douglas W. R.; Reinker, Kathryn I.; Clarke, Daniel E.; Itnyre, Amelia A.; Kabashima, John N.; Rust, Michael K. The Prevalence of Brown Widow and Black Widow Spiders (Araneae: Theridiidae) in Urban Southern California. Journal of Medical Entomology, Volume 49, Number 4, July 2012 , pp. 947-951(5) DOI: 10.1603/ME11285

Cite This Page:

Entomological Society of America. "Are brown widows displacing black widow spiders around southern California homes?." ScienceDaily. ScienceDaily, 2 July 2012. <www.sciencedaily.com/releases/2012/07/120702134436.htm>.
Entomological Society of America. (2012, July 2). Are brown widows displacing black widow spiders around southern California homes?. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2012/07/120702134436.htm
Entomological Society of America. "Are brown widows displacing black widow spiders around southern California homes?." ScienceDaily. www.sciencedaily.com/releases/2012/07/120702134436.htm (accessed July 24, 2014).

Share This




More Plants & Animals News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
Powered by NewsLook.com
Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins