In the evening of Sept. 13th, Ryan and I went for a walk along the Bonneville Shoreline trail, south of Dry Canyon. It had been a nice warm day, and we wanted to spend some time outdoors after being on campus all day.
As I was walking, I noticed a conspicuous silk structure in a sagebrush shrub on the side of the trail. My first thought was that it was a caterpillar tent. Several kinds of caterpillar live in colonies inside silk tents which they use for shelter. However, it seemed a little late in the year for a caterpillar tent, and I hadn’t seen any others in the area. Intrigued, I carefully pulled apart the branches that held the silk structure in place.
I was surprised to find that there were no caterpillars. Instead, a relatively big jumping spider appeared at the bottom of the structure. This spider was a tan color, and its large size made me think it was probably a species in the genus Phidippus. It occurred to me that this may be Phidippus octopunctatus, a species I had never seen before in the wild, but that had been documented and collected in the area by some of Jim’s previous graduate students. Like this spider, the specimens I had seen in our lab collection lacked any pattern and were tan in color. I later found a publication documenting the use of large silk nests by Phidippus octopunctatus.
I soon noticed that this female P. octopunctatus was relatively easy to photograph as she insisted in staying close to her nest. Jumping spiders are usually much more mobile and therefore difficult to photograph. I inspected the silk nest one more time. This time I was able to locate what seemed to be a round egg sac, but I did not look any closer as I did not want to disturb the nest too much.
Further along the trail, I noticed a large orbweb on a fence. It wasn’t too hard to find the owner, a Cat-faced spider (Araneus sp., probably gemmoides) resting on a metal post. The name of this spider originates from the shape of its abdomen, which has two anterior humps that make the spider look like a cat face. Cat-faced spiders are often found near homes, and typically close to a source of light. The idea is that lights attract insects at night, thereby increasing the spider’s food supply.
Curious about the identity of this shy crab spider, I gently pushed it out of the crack with a small twig. Thinking I would see a member of the genus Xysticus, I was surprised to notice that this spider appeared to be much flatter and darker in color than the Xysticus spiders I had collected in the area. This spider belonged to a different genus, Bassaniana, also known as the Bark crab spiders. These spiders, which are very flattened, are found almost exclusively on tree bark, wooden fence posts and the like where their color camouflages them. Like other crab spiders, Bassaniana waits to ambush its prey rather than actively hunting it.