Unfortunately I do not have the time to answer all the emails and phone calls that I receive regarding spider biology from the public-at least 4 a day. Although I do my best, many emails go unanswered (sorry folks). In an effort to help answer your questions, I've created this web page to address the most common inquiries. If you have more specific questions that you would like answered, I refer you to one of the following sites below for more information. This page (like all web pages) is a work in progress and will have additional information added as time permits. Check my frequently asked questions page (just started, please be patient) for some no-nonsense answers about spiders.
An excellent place to have your spider questions answered by a professional arachnologist. Unfortunately this site is run by volunteers. Consequently, they have limited amounts of time to devote to question answering and may not be able to answer all questions in a timely manner.
This is a listing of many professional arachnologist's web sites. You might be able to contact one of these specialists to have your questions answered.
1. I found a spider, what kind is it?
Spiders are sometimes difficult to identify to species even when the spider is readily available. Most species require careful examination of genitalia or other minute structures for positive identification. Therefore, it is nearly impossible to positively identify a species with only a verbal description. That being said, it is often possible to identify some of the more common families of spiders if you can give some more specific information. If the spider is fairly unique in some of its other general features (color etc.), arachnologists can often arrive at a very good guess as to the spider you have.
To help me (or any other arachnologist you choose to consult), you should give the following information for a best guess of the specimen that you have seen (or recently killed).
1. Where do you live? Some species or even whole families of spiders can instantly be eliminated as a possibility based on geography alone. This is an important piece of information. If you think you have a brown recluse spider and you live in Missouri--it may be true, if you live in Maine, it probably isn't.
2. What sort of general habitat did you find this spider? Your house? A grassy field? Maple leaf little in a forest? Under a log? etc. This too is very helpful information.
3. Was the spider in a web or near one? Also an important question. If it was in a web, what did the web look like? Was it a messy tangle web? A circular orb web? Was it flat like a sheet? Did it have a little retreat at one end that the spider was in?
Flat sheet with a small silken retreat in the corner of it The web isn't very sticky.---Probably a funnel weaving spider. vibrate the web very lightly but rapidly with a small stick-does the spider dart out onto the web?. Some of the most common species of this family are in the genus Agelenopsis. These you will often find in low vegetation or on grass. You may often see these in large numbers when dew sticks to their webs in the morning.
Flat web with a slight dome shape and the spider hanging directly below the dome--not in a a retreat. Probably a bowl and doily spider-
4. What color was the spider and how large? This is also useful information?
5. What was the spider doing? Behavior is often an important feature of identification. Was it on the wall? If so, an arachnologist can quickly eliminate many families right away. Was it oriented downward on a wall? Did it have some legs pointing forward and others back? If so, which ones?
6. Do you have a picture. Obviously this is a tremendously helpful item to help positively identify a spider.
2. I think I was bitten by a spider, how can you tell if it was a spider bite and are spider bites dangerous?
It is worth clarifying two important points, First, arachnologists are not medical doctors, or, more specifically, dermatologists, and have no formal training in identifying various skin conditions as spider bites or otherwise. This diagnosis should be done by a trained medical doctor. Second, medical doctors are not trained arachnologists nor entomologists and may not have intimate knowledge (or personal experience) about what a spider bite may look like or what sort of spider did the biting. Luckily, there are but a couple dozen species of spider worldwide (out of at least 36,000 species) that are known to have venoms that cause ill side effects in humans. Of these species, but 5-6 live in the United States (including exotics that ended up here) and generally do not go out of their way to bite a human.
Although I have no quantitative data, I suspect that the number of "accused" spider bites vastly outweighs the actual number of spider bites. If personal experience is worth anything, I have conservatively handled well over 10,000 spiders in my lifetime and have yet to be bitten. Many other professional arachnologists can claim the same. However, some spiders can and do bite. In general, their bites are no more dangerous than a small bee sting. Like bee stings, they are irritating and sometimes painful, but rarely dangerous. However, like bee stings, some people may be allergic to spider venom and have much more severe reactions than others.
Any skin condition that you are worried about should be checked by a medical doctor.
3. How do I know if my spider is a male or female?
It is often difficult to sex a juvenile spider or spiderling since the reproductive structures have not developed yet. If you happen to have an adult or subadult spider (often called penultimate when it is one molt away from being mature), males and females of any spider species are generally pretty easy to tell apart. All spiders have short appendages at the front of their bodies called pedipalps. These structures generally look like legs except they are much shorter. In females they look the same as legs except shorter. In males, they are rounded or bulbous at the end and serve as copulatory organs. Males literally suck up sperm into their pedipalps (sort of like a pipette bulb) and begin searching for females.
Also, female spiders are always bigger than the male-sometimes only slightly so, in other cases, up to 100 times larger. Males also tend to be more active and have proportionally longer legs and smaller abdomens than females. The majority of spiders (but not all) you find in your house crawling across the floor tend to be males since they are much more active and often travel great distances searching for females.