About 'Map the Spider'

Launched September 2019

Please pardon the awkwardness of the website layout etc. I'm currently typing HTML by hand to update things (ST) and barely know what I'm doing! And it shows. Let me know if you can help!

This site was launched in September 2019. We are asking for your help to find purse-webs near your home or places you visit. If you are not sure if something is a purse-web or not, you'll need to gently touch it. The purse-web silk will 'give' a little when you touch it, while non-web things like roots and dirt-covered termite tunnels are rigid.


Goal 1: Find out how common purse-web spiders are. Most people would never notice a purse-web unless they were shown what one looked like and then actually looked for them. Despite their camouflage, purse-webs can be found at any time of year and with a little practice are not hard to spot from a distance. Often many webs are found close together on a tree, a wall or in shrubbery. In the Philadelphia area once you start looking you notice them everywhere.
Goal 2: Determine the range of the PA-local spider Atypus snetsingeri. We know it's widespread in DelCo (anywhere near Cobbs and Darby Creeks, and many places near Crum and Ridley Creeks), but how far away can it be found? Are the purse-webs we find along the Brandywine, French Creek, Wissahickon Creek or at Valley Forge the same species? We're asking people in PA, NJ, and DE to report web sightings to provide a range of locations we can visit to get species IDs.
Goal 3: Develop non-destructive methods to tell the species apart.. Wandering males mostly look different, but these spiders spend 99.99% of their time within their webs hidden from view. How can we tell who lives in a web without disturbing the spider? One way is to look at the shed skins, or "exuviae," that often get stuck at the top of the purse-web when discarded. The exuviae preserve hard parts that we hope to use to distinguish different species, without digging up or killing any spiders.

Report purse-web sightings

Please use the MapTheSpider app to report sightings of purse-webs. The app is simple to use, works offline (away from cell towers) and only asks for the minimum information necessary to validate your sightings. Each Observer can use the app to track and map their own sightings and the places they visited, and at the same time it organizes all of the reported data for the project.

We also monitor the sites Bugguide.net and iNaturalist.org for reports of Atypidae sightings but won't use those for the map without independent onsite verification of webs. While great for posting your pictures, the app's purse-web validation questions aren't answered there.

Can we see your spiders??

Many good locations to look for spiders are on private property or 'Posted lands' that prohibit public access. If you have purse-webs on your property outside of Delaware County and are willing to let us visit to take photographs and measurements, let us know. Or if you have access to one of the many private woodlands or fenced-in corporate properties and can get permission for us to make a search, let us know. Send an email to contact us.

Not sure if what you see is a purse-web?

Other kinds of webs are present in the same habitats, but unless the web is ONLY a tube of silk it is not a purse-web. Check the pictures here. Purse-webs look tubular and sock-like, and will 'give' a little when you touch them with a blade of grass, while non-web things like roots are rigid. 'Tube-like' webs attached to silken sheets or platforms or a 3D trap in space are NOT made by purse-web spiders. For example, funnel-web spiders are common in the same places you find Atypids and make a sheet web that leads to a funnel with a hole, but those are not purse-webs.

Questions about spiders or webs?

Map The Spider is specifically interested in current (2020+) reports of purse-web sightings for building a map and collecting shed skins. If you have questions about any other spiders and invertebrates you find, including artifacts like webs, check out Bugguide.net or iNaturalist.org. Post a photo and volunteers will help you identify what you found, or just browse the images to see what others are seeing.

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