© by: Todd A. Blackledge 1997 |
 Several
species of Cyclosa can be found in the US. They are much smaller
than Argiope but also build stabilimenta. They sometimes build silk
stabilimenta but often add a line of debris or, in this case, a line of
egg sacs to their webs. The spider can be very difficult to distinguish
at the center of her web.The close-up shows a Cyclosa turbinata
that has been disturbed and moved onto its stabilimentum. The actual size
of the spider is only about 5mm. |
Another common,
but hard to find, spider is the Featherlegged Orbweaver, Uloborus glomosus.
These photos are of young spiders, less than 5mm in size, that were building
webs deep in sheltered locations in a grassy field. Like Argiope
and Cyclosa, Uloborus also tends to switch from building
circular or disk shaped designs to linear stabilimenta as they mature.
Unlike Argiope and Cyclosa,
Uloborus builds a horizontal
orb web. The sticky silk in the web is also unusual. The sticky silk in
most orb-weavers' webs has tiny droplets of gluey carbohydrates but the
silk of Uloborus and other "cribellate" spiders lacks this glue.
Instead a single silk strand is made up of thousands of tiny, fluffy tendrils
that give the silk an incredible surface area that helps the silk to adhere
to insect prey.
This Uloborus
has been disturbed and moved slightly from the center of its web. At rest,
the spider fits perfectly into the gap between the two arms of the stabilimentum,
making it difficult to see the spider. Uloborus mature in the late
spring and lay their eggs in the early summer. The young can be found building
webs in sheltered locations throughout late summer and early autumn.