Spiders of the World

Sample Analysis

• Trapdoor spider: The trapdoor spiders are very difficult to find and quite rare at most PINS with the exception of the Southern U.S., Mexico, Southern Europe and Bermuda sites. The high final number may be erroneous possibly due to a confusion with another family of spiders such as the purseweb spiders.
• Spitting spider: There are only 100 species of spitting spiders worldwide. Most are tropical and they are very reclusive making it difficult to find them. The sites where one may expect to find small numbers of spitting spiders include Mexico, possibly Hawaii and Bermuda. With the high final number, this spider was most likely incorrectly identified and confused with another family.
• Violin spider: There are only about 50 species of violin spiders worldwide and most are reclusive. Violin spiders are found at the European PIN sites as well as in North America. The high final number may have occurred as many students in North America including Hawaii are familiar with the Brown Recluse spider which is a poisonous violin spider and possibly misclassified spiders as the Brown Recluse due to its "fame".
• Comb-footed spider: There are 2,000 species of comb-footed spiders which are found at all PINS. The spiders are cosmopolitan and so would be easily found by all students. As a result, the high number of comb-footed spiders would be expected.
• Sheet-web spider: The final number of sheet-web spiders seems correct as it coincides with the geographical and numerical data.
• Large-jawed orb: There are 600 species of large-jawed orb weavers worldwide. There are large numbers in Hawaii and fewer numbers on the mainland. However, the spiders are usually easy to find and found at all PIN sites so the number of spiders counted is as expected.
• Orb web weaver: The final number of orb weavers seems correct as it coincides with the geographical and numerical data.
• Funnelweb weaver: There are only about 600 species of funnelweb weavers. However they common in most of North America and in Europe and easy to find so the high final number would be expected.
• Wolf spiders: There are 3000 species of wolf spiders worldwide. They are common at most of the North American PIN sites where most of the data was received from. As a result, the high number is as expected.
• Lynx spiders: There are about 500 species of lynx spiders worldwide. A relatively low final number would be expected.
• Sac: Sac spiders are proportionally more common in North America and especially in Mexico. They are rare in Europe. This may explain the relatively high number of spiders counted. However, the number is still quite high.
• Crab spiders: Although there are only 2000 species of crab spiders they are common and easily identified. As a result, the high final number is as expected.
• Jumping spiders: Jumping spiders are common and obvious. The high final number is large but is as expected.
• Dictynidae: There are only 500 species of Dictynids. However, they are most common in North America and Europe so the final numbers is as expected.
• Nurseryweb spiders: There are 600 species of nursery web spiders worldwide. There are relatively few found in North America and fewer in Europe but they are easy to find and obvious. The high final number is still a little too large.
• Uloboridae: There are 200 species found worldwide. However, one would expect to have counted some.
• Daddy long legs: There was some confusion about daddy long legs as there exists 800 species of a non-spider and 300 species of a spider family. The non-spider, from the family Phalangiidae is very common in temperate areas and explains the high number of daddy long legs counted. However, the real spider is tropical and most common in the Mediterranean.

Spiders of the World

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Gene Carl Feldman (gene@seawifs.gsfc.nasa.gov) (301) 286-9428
Todd Carlo Viola, JASON Foundation for Education (todd@jason.org)

Last revised: 19 May 1995 ( )