Howdy BugFans,
It鈥檚 almost time for Snowbirds to head back north to rejoin us here in God鈥檚 Country for the final days/weeks/months of winter. The BugLady read recently that the number of days below freezing in March here in God鈥檚 Country has听drastically听decreased in the past 25 years, and March is increasingly considered a spring month rather than a winter month (but when the BugLady was a kid鈥︹��..). The temperature may be moderating, but March still has plenty of tricks up her sleeve, and most of them involve snow.
BugFan Tom supplied the pictures of this big, beautiful spider that inhabits the South from Virginia to Texas (and beyond, to Argentina and Peru).听Thanks, Tom.听
The brightly-patterned females may be more than two inches long with a five-inch leg span, (males are much smaller ). A spider this big (probably our largest orb weaver) that makes big webs necessarily gets noticed and collects lots of names, like Banana Spider, Golden Orb Weaver, Calico Spider, Golden Silk Spider, and Giant golden Orbweaver, and people who walk into the webs while hiking probably have other names for them.听MUCH has been written about their golden silk 听鈥� more about that later.
The Golden silk orb weaver (Trichonephila听clavipes) was formerly known as听Nephila clavipes. Nephila听means 鈥渇ond of spinning鈥� and听clavipes听means 鈥渃lub-footed,鈥� possibly a reference by Linnaeus to the dark tufts of hair on six of the female鈥檚 legs.听Recently, it and a dozen other genus members were moved to the genus听Trichonephila听– the Golden orb weavers.听Historically, GSOWs were the only member of that genus in North America, but in 2014, an East Asian species called the Joro spider found its way to Georgia, and it鈥檚 been spreading out through the Southeast .听听听
Look for GSOWs in open areas in woods or edges, preferably near wetlands or coastal areas.
Male GSOWs spin trap webs until they reach maturity, but then they set off to find a mate.听When they find a female鈥檚 web, they quietly move onto its periphery and feed on some of the prey she catches, and a female鈥檚 web may host a number of males.听Dewdrop spiders Dewdrop Spider 鈥� Field Station and Spiney-backed orb weavers Spinybacked Orbweaver鈥� A Spider for Snowbirds 鈥� Field Station also live on the web鈥檚 outskirts and share in the bounty.听An amorous male will approach the female while she is distracted by a meal, and he signals by vibrating both the web and his abdomen (he鈥檚 cautious, but there鈥檚 not a lot of sexual cannibalism in this species).听Males don鈥檛 produce much sperm, and they replace it slowly, so they favor newly-molted females who have not mated yet.听After he mates/attempts to mate, a male may move on to a new web.听
Females place two or more egg sacs, each containing a few hundred eggs, on surfaces near their web .听Hatching may be triggered by environmental cues in their damp habitats. The spiderlings stick together for about a week after hatching , and then they disperse.听By late summer, the tiny spiderlings of spring have reached full size and are making conspicuous webs.
This is a big spider that builds a big, strong web (up to six feet in diameter) that is capable of snagging some big prey, like moths, fast-flying horse flies, dragonflies (which are both GSOW eaters and eat-ees), butterflies , beetles (this one is June-beetle-size) , cicadas, and grasshoppers.听Though they trap both small and large prey, they prefer to eat the bigger insects.听
The webs are sturdy enough to capture birds. Daniel M. Brooks, in an article titled 鈥�Birds Caught in Spider Webs: A Synthesis of Patterns鈥� published in the Wilson Journal of Ornithology (2012), wrote that a review of international literature and list servers found 69 accounts of birds trapped in webs.听Nephila听species, especially GSOWs, accounted for half of the reports of mostly hummingbird-sized birds (though a small dove was reported, and the author personally observed a Swainson鈥檚 thrush tangled in a web), and while some were able to free themselves, a significant number had been killed and wrapped by the spider.
The asymmetrical, orb-type web is usually located between two and eight feet off the ground (but may be at treetop height). When prey is abundant, GSOWs may cache as many as 15 wrapped insects in a 鈥渂arrier web鈥� – a debris-strewn area along one side that serves to warn/block predators and help keep the web clean.听One source said that the organic waste held in the barrier web may attract insect prey by its odor.听
GSOWs鈥� main predators are wasps that collect them to provision their egg chambers, and birds.
Unlike many species of orb weavers that replace their webs daily, eating the old web to harvest its protein, GSOWs repair damaged webs.听Researchers believe that the yellow tint, the intensity of which the spiders can control, may attract bees, and it may also help to camouflage a web in the shade.听A number of females may make webs close to each other .
This is some serious silk!!!听Nephila/Trichonephila听silk has a high thermal conductivity, is stronger, by weight, than steel (it鈥檚 being studied with hopes of replicating its extreme strength), and it has some interesting medical applications.听Wikipedia reports that it may be beneficial in surgeries involving the nervous system because it may guide and encourage neuronal regeneration.听
Wikipedia also reports that hunters in New Guinea make fishing nets from the silk.
Finally, enterprising folks have experimented with it as a textile, creating garments (thanks to the labors of millions of spiders) .听
FUN FACT ABOUT SPIDERS: the tips of the legs of spiders that wander around and don鈥檛 make trap webs point outwards, and the tips of the legs of trap-web-spinners point inwards.
FUN FACT ABOUT NEPHILA/TRICHONEPHILA SPIDERS: The genus Nephila is not only the oldest-known surviving spider genus (165 million years), but it includes the largest-known fossil spider.
The BugLady