Banded argiope spiders represent some of the largest orb-weaving spiders that we have in Montana. With their conspicuous coloration and size, they are noteworthy spiders in meadows and fields in late summer. Along with other spiders in the genus Argiope, they are known as garden spiders.

Description:

A banded argiope spider sits on a clear surface. The web is visible and the top two knuckles of a human finger is present. The spider is as large as the visible finger.

Figure 1. Female banded argiope spider, Argiope trifasciata. Photo by L. Kerzicnik

The females are large spiders (can reach up to 25 mm). Theirabdomen (2nd segment) is striped with silver, white, and yellow. Males areabout 1/4 of the size of females (reaching up to 6 mm).

Behavior:

They tend to be in meadows with high grasses and like to make webs on goldenrod. They prefer drier habitats compared to some closely related species. Their webs are large and spiral shaped. The web also has a zig-zag decoration in its center called a stabilimentum that extends above and below the center, which serves as a possible camouflage or to attract prey (its function is not entirely understood). The females tend to hang in the middle of the web during the day. They feed on a variety of prey that they capture in their webs. They tend to feed on several grasshoppers when they are present in the surrounding meadows.

A banded argiope spider sits on a stick.

Figure 2. Female banded argiope spider, Argiope trifasciata creating an egg sac. Photo by L. Kerzicnik

Life cycle:

Argiope spiders live less than a year. The females mature in late summer/early fall. The female dies after making an egg sac. The egg cocoon is brown and papery and sphere-like in appearance. Each sphere contains 400 to 1000 yellow eggs. Very young spiders overwinter in the egg cocoon and emerge in April or May.

 

To learn more about the topics discussed on this page, contact the Schutter Diagnostic Lab.  If you suspect an infestation on your property, contact your local extension agent, the Schutter Diagnostic Lab at Montana State University, or the Montana Department of Agriculture.

 This November 2022 fact sheet is also available as a printable PDF (253KB). 

 

Disclaimer: These recommendations are provided only as a guide. It is always the pesticide applicator’s responsibility, by law, to read and follow all current label directions for the specific pesticide being used. The authors and Montana State University assume no liability resulting from the use of these recommendations. The Montana State University Extension Service is an ADA/EO/AA/Veteran’s Preference Employer and Provider of Educational Outreach.