Map the Spider

Help make a map for the Philadelphia purse-web spider

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Last on:
28 Aug 2022

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Purse-web spiders (Mygalomorphae, Atypidae) are primitive and secretive animals, related to tarantulas, that spend most of their time in an underground burrow within the lower part of their 'sock-like' tubular web. The silken tube extends up from their burrow above the ground to where it is often attached to a tree, shrub, boulder or wall. Sometimes several smaller webs are built close together forming groups of 3-10 or more. The webs are well-camouflaged with dirt and debris, often looking like a root, and the spider catches prey that walk on it. Very Jedi. Purse-web spiders live for several years and many of their webs are durable enough to withstand seasonal damage and repairs to be seen at any time of the year.

In North America all purse-web spiders are in the genus Sphodros - except for one, Atypus snetsingeri, which was only reported from two sites in eastern Delaware County, PA, near Philadelphia. We know now the spider is more widespread in the region, and webs have been reported in habitats ranging from forest and woodlands to neighborhood hedges and gardens. This project asks people to look for and report sightings of purse-webs in the Philadelphia region to develop an estimate of the spider's current range and distribution.

Recent DNA evidence indicates that our 'Atypus snetsingeri' is actually a naturalized East Asian species, 'Atypus karschi'. No one knows how long the spider has been here, but theoretically it could have hitched a ride as far back as 1784, hidden among potted plants, when direct shipping began from China to the port of Philadelphia in the newly-independent United States of America. Your help in reporting web locations will help identify the 'boundaries' of the spider's range and how common it is in different areas. A good map may help unravel the spider's history here.

Use the Epicollect5 application to report where you searched and for how long, and whether or not you found any purse-webs (both kinds of data are important!). Help us make a definitive map for our local purse-web spider.

Spiders are cool, but purse-web spiders are *very* cool. See if you can find the spider in your neighborhood!
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