Spider beauty in October

Cross Orbweaver (Araneus diadematus). Photo Jeff Koziol

When Jeff Koziol and Gisela Kutzbach did the final round of winterizing the Biocore Bluebird trail nest boxes on a sunny October morning, we found some interesting spiders. One was clinging to the underside of a nest box and the other happened to cross on the path ahead—so big and so striking we had to notice. We send the photos for identification to Tom Morgan, newest member of the Friends.

Tom, an insect specialist with a fondness for beetles suggests, from information on the web, "that the spider with the white markings is a female of Araneus diadematus, the cross orbweaver (that also has other common names). There are hundreds of species in the genus Araneus, but this one seems to be A. diadematus, which is a naturalized immigrant or nonnative species that now occurs throughout much of the northern areas of the new and old worlds." Tom adds, "I tend to get more excited about insects such as large beetles, but this is a beautiful spider".

​Orbweavers are those spiders that spin their webs in the classic, round and flat shape, with spokes radially going from the center outward. These webs, usually constructed vertically to the ground, are perfectly photogenic in the early morning sun, with strings of dew drops still clinging to the strands. The cross orbweaver Jeff and I saw was about 3/4" long, with its abdomen swelled by the hundreds of eggs it carries at this time of year. See more details on the BugLady Field Report. 

The spider species Araneus diadematus, commonly called the European garden spider, has "colorings ranging from extremely light yellow to very dark grey, but all A. diadematus have mottled white markings across the dorsal abdomen, with four or more segments forming a cross. The markings are formed in cells filled with guanine, which is a byproduct of protein metabolism" (Wikipedia). Watch the fascinating movie on the Wikipedia gallery on how a courting male is consumed by the female spider.

If you happen to photograph any interesting beetles—or spiders—in the Preserve, please send them to perserveFriends@gmail. Also, Mark Nofsinger has posted on iNaturalist an impressive collection of insect photos seen in the Preserve.

Photo Jeff Koziol