Wh-a-a-a-t? Another Red Spider?!

I am seeing a theme developing here. Last week I posted about a lovely little red spider I found in our back yard. Today, I bring you a slightly larger red spider that I spied at Graham Cave State Park in Missouri, USA. This one, Hypsosinga rubens, is an orbweaver, but because it spins its web in a horizontal plane, I initially mistook it for a female of the Scarlet Sheetweb Weaver.

A friend who was with me at the time I saw this diminutive beauty commented that she sees them all the time, and calls them "tomato spiders" because of their bright red color. Well, at only 7.4-8.7 millimeters in body length, maybe *cherry* tomato spider is a better name. The only common name I find is Rubens Orbweaver. Males of this species are smaller still, 6-6.5 millimeters, and they usually have a black abdomen.

There is great variability in color and pattern, or lack thereof, and a typical female from Florida has a white abdomen with small black markings. The Rubens Orbweaver occurs over most of eastern North America, but there are scattered records from the Prairie Provinces in Canada.

Beyond the bright color of this spider, the thing that surprised me was how ridiculously small its web was, stretched between a couple of leaves on a shrub at a little over waist-height. I expected her to drop out of the web if I approached too close or moved suddenly, but she stayed put in the hub of her snare. Information in the literature indicates that they may also shelter under bark on trees, or tuck themselves under leaf litter. I found mine along a forest edge, and forests are their preferred habitat.

Sources: Bradley, Richard A. 2013. Common Spiders of North America. Berkeley: University of California Press. 271 pp.
Hollenbeck, Jeff. 2007. "Species Hypsosinga rubens," Bugguide.net

Aculepeira Orb Weavers

It takes little to excite me when I am out in the field, but back on July 13 I happened upon a spider that was new to me. My wife and I were hiking in Lovell Gulch, just outside of Woodland Park in Teller County, Colorado, enjoying the mixed conifer and aspen forests at an elevation of roughly 8,500 feet. I seem to recall watching an insect in flight when an orb weaver spider caught my attention.

The underside of the spider was most visible as it sat in the hub (center) of its wheel-like web, so I maneuvered as best I could to get a dorsal (top side) view. My initial thought was that this was a spider I had seen dozens of times: the Western Spotted Orb Weaver, Neoscona oaxacensis. Still, something seemed a little bit "off," and sure enough the ventral markings on this spider's abdomen were very different from that of a Neoscona species.

Underside of A. packardi

Underside of Neoscona oaxacensis

Once I got back home, I tried my hunch that it might instead be a species of Aculepeira, even though I had never seen a specimen before. Indeed it was. It turns out that this genus is pretty much restricted to high elevation, and/or high latitude habitats. The three North American species are collectively found from Alaska and the Yukon Territory to northern Mexico. There are also a few records in the northeast U.S. One undescribed "prairie species" has been discovered in western Washington state.

This one is almost certainly Aculepeira packardi, but it takes a microscopic examination of the genitalia of adult specimens to be conclusive. Note that the species name in older references is spelled with two "i"s: A. packardii. The other two species here are A. carbonarioides and A. aculifera (which reaches Guatemala).

Normally, the adult female spider hides in a silken retreat on the periphery of her web during the day, but this was a mostly cool, overcast day, so she may have felt comfortable occupying the center of her snare. The web was strung between the branches of a very low-growing shrub on a gentle slope in an open meadow.

These are good-sized spiders, mature females averaging nearly 11 millimeters in body length, males about 6 millimeters. The markings are pretty consistent, too, which does help a little bit in determining the species.

Interestingly, A. packardi also ranges in the Russian far east, Siberia, and northern China. In North America, it ranges from the Yukon to Labrador, and south to Chihuahua, Mexico and Pensylvania.

One typical dorsal pattern of Neoscona oaxacensis

From now on I will always double check spiders that I "think" I already know. It is a good practice, for you never know if you will find something new; new to you, or even new to science. All text and images © Eric R. Eaton

Sources: Balaban, John and Jane, et al. 2015. "Species Aculepeira packardii," Bugguide.net.
Dondale, Charles D., James H. Redner, Pierre Paquin, and Herbert W. Levi. 2003. The Orb-weaving Spiders of Canada and Alaska (Araneae: Uloboridae, Tetragnathidae, Araneidae, Theridiosomatidae), The Insects and Arachnids of Canada Part 23. Ottawa, Ontario: NRC Research Press. 371 pp.
Schimming, Lynette. 2013. "Genus Aculepeira," Bugguide.net.