Black-and-Yellow (St. Andrews Cross) spider egg sacs
Location: San Antonio, TX
January 19, 2011 3:38 pm
No ID needed. I know what these are, thanks to your site a few years back, but I had to attach a photo to get the query to SEND. I am requesting some info, now, though. — I collected several ”jar” egg sacs which were made by some very big and beautiful Black-and-Yellow spiders. The exterminator was gong to blast them (the sacs; the mothers have already passed on with the weather). They were in Floresville, TX, and are now clothes-pinned to my patio plants here in San Antonio. I’d really like to know how to protect them and keep the babies inside safe over winter and have them come out in the Spring and populate my yard. What will they need to survive? I understand the babies hang around the ”jar” for the first few days, then disperse. Would it be good to house them in some kind of spider nursery (if so, please could you suggest something)? Is dangling and moving in the wind going to disturb the babies? The ”jars” w ere securely stitched into immobility under the eaves at the ranchhouse where the mother spiders put them. Would very much appreciate any and all info you can offer. — LOVE your site. Thank you for all the good you do for insects, bugs, and all.
Signature: sooz in San Antonio
We are very happy you attached an image. First, we would much rather post a letter with an image than without one, and second, you have misidentified your spider. The St. Andrew’s Cross Spider, Argiope keyserlingii, to the best of our knowledge, has not been found in North America. It is an Australian species that has a unique X shaped stabilimentum, the zigzag pattern that is woven into the web. You can see images of the spider and its stabilimentum on the Brisbane Insect website. Your spider is in the same genus, so the mistake is understandable. Your spider is a Golden Orbweaver, Argiope aurantia, and its stabilimentum is different. You can see images in our archives and on BugGuide. You should keep the eggsacs in a protected location away from the wind and predators like birds, but make sure that they are kept at approximately the outside temperature. Perhaps a paper bag or a cardboard box left open in a sheltered area of the patio or unheated garage would suffice.
THANK YOU! And I’m glad to have their correct name. One last question (OK, two): What can I expect when the babies emerge? And when should I expect them? — Thanks again!
When the spiderlings emerge in the spring, you can expect a crawling mass that will soon seek higher ground. The spiderlings will then each release a strand of silk to catch the wind and they will begin to balloon away. This is how they disperse, ensuring that the entire brood does not remain in a single location competing with one another for the food supply. The wind is actually capable of carrying the young spiderlings a considerable distance.