Mon, Oct 6, 2008 at 7:47 PM
I’ve seen this spider on the other side of my window every night now for about a month. It lives in the crevice of my window during the daytime and at night it comes down and sits in the middle of its web. Its underside is black with two small white dots, and its a little bigger than a quarter. I’ve done my research and my best guess is that it’s a barn spider. I don’t know if I can include links or not but I also have a video of it here: http://www.youtube.com/watch? v=qYO1y9cygQ0 (ignore the TV in the background)
San Angelo, (West) Texas
Your spider surely does look like a Barn Spider. Species in the genus Neoscona are commonly called Spotted Orbweavers and, according to BugGuide: “Some species (usually collectively referred to as “barn spiders”, i.e. Neoscona crucifera ) are nearly impossible to distinguish from Araneus and can only be separated by examination of carapace to view the carapace groove (fovea). Neoscona have a longitudinal groove on the carapace (parallel with the long axis of the body), whereas Araneus have angular (transverse) grooves. However, an apparent problem is that in Araneus the groove may appear as little more than a dimple, making it tough to tell. See this diagram for differences in the carapace grooves.” We have never taken identification quite that far, and due to individual variation within the species of Araneus and Neoscona, it is sometimes quite difficult for us to get more specific than to just identify a spider as an Orb Weaver. We did find a nice chatty comment about the nocturnal habits of Neoscona hentzi or Barn Spider on an amusing website called Nature at Close Range. Also, according to BugGuide, Neoscona hentzi is synonymous with Neoscona crucifera. It is embarrassing for us to admit it, but we haven’t ever bothered positively identifying our own species of Orbweaver. Our own nocturnal spinners get quite numerous in the autumn and they spin webs all over our garden and patio. We had three large females spinning webs in close proximity to one another and our front porch light for weeks, but a few days ago, there were just two. We have wondered about the fate of the third as her web remained in place from day to day, getting more and more tattered, while her sisters consumed their own webs each morning and resumed spinning anew when the sun sets each evening. Since we have never gone to the extent of examining the anatomy of our own individuals, and are not certain of their exact genetic lineage, we can’t rule out entirely that they might have hybridized with other introduced species. Geographical barriers that once separated individual populations from one another have been breached by man who is responsible for accidental introductions of many exotic specimens into new habitats. Sometimes this has dire consequences, and sometimes these introductions may go unnoticed. We figure the spiders know best about mate selection, and species and subspecies are only categories created by humans in a feeble attempt to better understand the world around us. Future taxonomists may even determine that Araneus and Neoscona need to be lumped together into one super-genus, but the bottom line is that the spiders know and we only presume to know. We think Charles Hogue had the right idea in Insects of the Los Angeles Basin when he identified Neoscona oxacensis (probably a misspelled Neoscona oaxacensis or Western Spotted Orbweaver on BugGuide) as the Common Orb Weaver and wrote: “This is our most common orb weaver; in late summer and fall, its moderate-sized webs adorn gardens everywhere in the basin.”
P.S. We are getting used to the nuances of our new website and we are pleased that we can include the date we received a letter in the body of the posting, and can allow our program to time stamp the actual posting date. Your letter marks the first time we are including this double date.