Bowl and Doily Weavers

Frontinella communis Web

Bowl and Doily spider webs

I often see the webs of Bowl and Doily Weavers (Frontinella communis) in the shrubs surrounding our cabin near Grayling, Michigan. This spider is also called by the later name of Frontinella pyramitela.

Frontinella  communis Waiting on underside of web

Bowl and Doily spiders waiting on underside of webs

On dewy mornings in late summer and fall the small webs sparkle in the sunlight. A large web is 150mm (6 inches) across and our field can have 50-100 webs. As the common name states the web looks as if it is a woven doily stretched under a bowl. It is one of the most distinctive webs in the Great Lakes Region. The bowl portion of the web collects debris, leaves, twigs, and dust and lasts several weeks. It is repaired but not replaced. The spider hangs from the underside of the bowl. Trip lines span the supporting twigs over the bowl and always look fresh. Insects fly into those lines and then drop onto the sticky bowl. After the spider retrieves its prey it sits on the doily portion to eat.

Frontinella  communis Bowl and Doily Spider

Bowl and Doily spiders up close

After years of seeing these webs I recently found the spider that spins them. It is only 3 or 4mm (3/16 inch) long. The females are slightly larger than the males. This species’ white markings on the abdomen are distinctive. Male and female spiders sometimes share the same web.

I spied a spider on a web about 3m (10 feet) off the ground. After photographing the web I climbed a stepladder to photograph the spider. I normally work with a camera mounted to a tripod and stand on firm ground. I managed to get a few photos and not fall off my perch.

Michigan Nature Guy

Michigan Nature Guy

Copyright 2014 by Donald Drife

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Goldenrod Crab Spiders

Male Goldenrod Crab Spider

I recently photographed what I thought was a different species of spider only to discover that it is a male Goldenrod Crab Spider (Misumena vatia). The male’s body is quarter the size of a female and they often hide on the underside of leaves. They feed on insects (sometimes ones that the females catch) or nectar.

Female Goldenrod Crab Spider

Crab Spiders get their name because they resemble seashore Crabs. Their front two pairs of legs are much longer than the back pairs and they often move sideways on a flower in a crab-like manner. They do not spin webs but hunt by sitting still, camouflaged on a flower, waiting for insects and grabbing them with those long front legs. They have excellent eyesight and must be approached carefully to avoid startling them.

Individuals change color (slowly over a few days) to match the flower they are hunting from. Their color palette is white, yellow, and rarely pale pink. Red, blue, and purple are outside of their range. Studies show that the coloration does not correlate with hunting success. White spiders have the same success rate on white, yellow, or even blue flowers (See Brechbuhl, Casas, and Bacher).

The presence of Crab Spiders on flowers does change the pollinators that visit the flowers. Smaller bees avoid flowers inhabited by spiders but visits from larger Bumblebees are unaffected. It is presumed that the larger bees are not preyed upon by the spiders (See Dukas and Morse).

Male (smaller) and Female Goldenrod Crab Spider

Although Crab Spiders spin no web, they still produce silk. It is used as a drop line to escape predators and to cover egg sacs. They hide egg sacs, attaching them by silk to the underside of a leaf and then wrapping the leaf around the egg sac to protect it. The baby spiders are mini-copies of the adults and go through several molts before reaching mature size. Immature spiders overwinter and it is bizarre to see them on a warm day walking on the snow.

If you want more information on spiders, consult Larry Weber’s excellent book Spiders of the North Woods, part of the North Woods Naturalist Series. It is published by Kollath+Stensaas Publishing.

Works Cited

Brechbuhl, Rolf, Jerome Casas, and Sven Bacher. “Ineffective Crypsis in a Crab Spider: a prey community perspective.” Proceedings of the Royal Society 277 (2010): 739-746. Web.

Dukas, Reuven, and Douglass H. Morse. “Crab Spiders Affect Flower Visitation by Bees.” OIKOS 101 (2003): 157-163. Web.

Weber, Larry. “Spiders of the North Woods.” Duluth: Kollath+Stensaas Publishing, 2003. Print.