Cross Orbweaver

Description:

Size: Body length of mature female 6-20 mm; males 6-13 mm. Color: Beige to brown to orange, sometimes nearly black. Pattern of white spots usually present on top of abdomen, suggesting the shape of a cross. This pattern can vary considerably, or be almost entirely wanting in some individuals; underside of abdomen mottled with central black area framed by pale ‘L’-shaped brackets. Legs usually banded with brown or orange and ivory. Eyes: Eye arrangement typical of orb weavers. Total of eight eyes. Legs: Legs in proportion to body size; relatively thick and very spiny and hairy. Body: Abdomen broadly oval (tapers towards spinnerets); very large in gravid female specimens. Adult male’s abdomen is incredibly small when compared to female’s.

Habitat:

Range Found in the northern third of the United States and adjacent southern Canada (relatively non-existent in the Great Plains area, though, and now established in the northern half of California). This is an introduced species from northern and western Europe. Considered a “holarctic” species, it also lives in Asia. Habitat This is an abundant spider in yards, gardens, farms, orchards, urban and suburban areas throughout its North American range. It also frequents forest edges, riparian corridors, and old fields. Can be found low to the ground or high up (you can even find them on the outside of skyscrapers, as a result of the “ballooning” they do as spiderlings).

Notes:

I found this spider on my back deck while I was doing some work outside. I took note and was going to take a picture of it when I took a break. Well, I accidently broke the web while stacking something nearby, and the spider scurried up to hide under a slate roof tile. Fortunately, there was a new one up soon after and that is when I took this photo. Web Large, vertical, orb-shaped web is usually built at least 2 feet off the ground amid shrubs, trees, tall weeds, fences, buildings, etc; they are opportunistic and will use whatever “framework” they can. Though the actual orb of the web may be only a foot or two in diameter, the tether lines can be 6 feet or more, depending on where the web is situated. Web may be attached to buildings in urban and suburban areas. The spider may either reside inside a retreat at the periphery of the web, or occupy the hub (center) of the web, hanging head down. A signal thread may connect the retreat to the hub of the web for alerting the spider of prey. The spider eats the web every night, recycling the proteins and water and using them to re-build a fresh web. Season This is one of the few orb weavers readily found at all stages of its development, though mature spiders are the most conspicuous, from summer through late autumn. Some individuals emerge from the egg sac in the spring and reach maturity in a single summer, while others overwinter as juveniles and mature the following spring (the latter scenario is most common). Food Prey is flying or jumping insects that are intercepted by the vertical orb web. Life Cycle Male spiders mature ahead of females and may pair up with immature females, waiting for them to become sexually mature. Females spin egg sacs in late summer or autumn that are about 20mm in diameter and comprised of golden silk. They are constructed (seemingly “plastered”) in a protected place somewhat away from the web, sometimes attached to the eaves of buildings or inside rolled-up leaves or other foliage. Female dies shortly after laying her eggs. Each egg sac can contain anywhere from 100 to 800 yellowish eggs. Typically, only one egg sac is made per female. Spiderlings emerge from the sac the following spring and remain clumped together for a day or two until they are accustomed to the outside temperature, after which they disperse. Some spiderlings “balloon” to other locations by riding the air currents, while others stay relatively close to where they were “born.” Spiderlings are bright yellow with a black triangle toward the rear of the abdomen (though this is a generic pattern among many very young orb weavers). Even the spiderlings create a very cute, tiny, orb-shaped web.