Documenting the Spread of the Brown Widow Spider
Think you have a Brown Widow?
Let us know!
The brown widow spider has become well established in southern California in the early part of the 21st century and is still rapidly expanding its range. Arachnologists at UC Riverside would like to document the range expansion of the brown widow as it moves into new areas in California. As of 2009, the spider was known almost exclusively from Los Angeles, Orange and San Diego counties but as of 2010, it is starting to show up in Santa Barbara and Sacramento Counties. Please do not send any material from LA, Orange, San Diego and Riverside counties.
Outside of California, brown widows are known from Texas to South Carolina. We do not need any material from these states, but we would be interested in specimens found elsewhere.
In order to document the spread of the brown widow in California (as well as neighboring states), spiders must be examined in person at UC Riverside because many people misidentify immatures of the native black widow spider as brown widows. Therefore, if you would like to contribute to a scientific study, we would welcome any submissions sent to our campus. The spiders need to be sent to UC Riverside for examination; unfortunately, we can’t just take your word on this because of the possibility of a misidentification. If you can send electronic images, that may be acceptable as long as the pictures are in very good focus and you can get close enough to show detail.
Because the spiders are already found in California and are not very dangerous, they can legally be mailed alive. Put a spider in a small unbreakable container with a small piece of wadded up paper towel. The paper towel gives the spider something to hold on to during shipping. DO NOT put air holes in the lids. DO NOT mail the spider with a cricket or something else to eat on its trip. DO NOT add a moistened cotton ball or any other material (the cotton ball will act like a cannonball and pummel the spider to death during shipping). Put one spider per container if you send more than one; then again, only one good quality spider is needed from each location in order to verify its existence. Pack the spider with protective material like packing peanuts and mail.
If you mail dead spiders, it would be best to soak the spider in rubbing alcohol (or ethanol if you have access to it) for a few days to preserve the specimen. Then on the day of shipping, pour off the alcohol (you should not mail alcohol unless you know all the regulations that are needed to do so) and send the spider damp in a small leakproof container.
If you send electronic images, they MUST be in focus and be as close as possible. The most diagnostic feature that would be used for determination is the spots on the top and sides of the abdomen. The hourglass is not as diagnostic because some native black widows have a faint orange hourglass before they mature. If you mail a package and want verification of the ID, include a return address or a CLEAR and LEGIBLY PRINTED email address.
PLEASE DO NO SEND ANY MATERIAL FROM LA, ORANGE, SAN DIEGO AND RIVERSIDE COUNTIES
Mailing spiders or egg sacs or sending electronic images
Because this is a scientific survey, the following information is needed in order to document the spider’s existence:- State
- County
- City/town
- Date of Collection
- If you wish to include other information like where the spider was found (e.g., under an outdoor picnic table), that will also be welcomed.