Entomologists divide spiders as hunters into two broad categories: ambushers and trappers. Some of the ambushing spiders prowl about and sneak up on their prey; others like the Crab Spider, sit very still in a flower blossom and wait for visitors.
Among the trappers, there is a further division of the category by the type of trap or web. Some of the smaller trapper spiders, such as the House Spider spin a unconstructed, cottony sheet of fibers to catch their prey. Other trapper spiders, the Orbweavers, such as this type, the Spiny-bellied Orbweaver, and the Common Garden varieties, spin a complex, structured web to capture unwary visitors.
The Cross Orb Weaver has similar leg bands to its cousins, but it is considerably hairier; it differs also in not displaying the bright yellow and white torso markings of the Garden Spiders. Its dark color and the dull brown hair with which it is covered are consistent with its more reclusive nature.
Unlike the Garden Spiders, which are content for me to move in closely to get a picture, this type is easily disturbed and will abandon its web to flee to a place of safety in some dark corner if approached too closely. Araneus diadematus seems to favor locations on structures rather than out in the garden on vegetation, as do the various Garden Spiders. And, as I learned recently, it will also build its web in the bed of a 1989 Ford F150 pick-up truck—mine!
As I went out to haul some supplies from the local hardware store one morning, I looked down and discovered that this Cross Orb Weaver had set its web trap across the bed of my old truck. Because I managed to bump against the side of the truck, it disappeared, most likely, I knew from experience, to be gone for the day.
Knowing it was a nocturnal predator, I returned early the next morning and there it was!
By exercising some care this time, I managed not to alarm this normally skittish spider. Because it had strung its web between the sides of my truck bed, I was able to get my images from several vantage points, with minimal disturbance. (Other times I've been limited to crouching under a porch or deck overhang, which made stealth almost impossible.) All and all, this was a most favorable "sitting" for this most elusive subject!
When I first arrived early on this foggy August morning, it was busily engaged in wrapping an ensnared Yellowjacket (Member of the hornet family—Vespula squamosa) in a silken shroud. The perspective above is edgewise, across the plane of the web, just as this trapper began to wrap its catch.
Here is another shot through the web, edgewise. Reaching through the glistening strands Araneus diadematus ran a cord around the paralyzed hornet.
In less than a minute, (above) this was the final package, ready to set aside for the next generation's hatchlings first meal.
Another interesting contrast between this spider and its Garden Spider cousins is the difference in the patterns of their webs, even though both species spin an orb web; this type's is shown below.
Look closely and you'll see the irregular angles of the cross strands that extend between the radial elements, thus the Cross Orb-Weaver name.
The way the silken lines are laid out, one might think it started in one direction, then changed its mind, and .... No, and its not that the web has had repairs over time; a freshly constructed trap has the same disjointed look.
The Garden Spider, however, builds its webs with a consistent approximation of a right angle between the main radials and strengthening cross lines. Interesting contrast, isn't it? (This view is color-shifted to emphasize the structure of the web.)