Black-and-Yellow Garden Spider

Argiope aurantia — the black-and-yellow garden spider, also called the corn spider, the writing spider, or the zipper spider — is one of the largest and most familiar orb-weaving spiders in North American gardens. Females reach 28 mm body length and weave webs up to 60 cm across, typically anchored between tall garden plants in late summer. The most distinctive feature is the stabilimentum: a thick zigzag of denser white silk woven into the center of the web. The stabilimentum has been the subject of over 100 years of scientific debate. Hypotheses include: (1) UV reflectance attracts pollinator insects to the web (supported by some experiments), (2) physical reinforcement of the web (mostly rejected), (3) visual warning that prevents birds from accidentally flying through and destroying the web, and (4) predator deterrence by making the spider's outline harder to see. The current consensus is that the stabilimentum probably serves multiple functions and that different functions may dominate in different ecological contexts. The black-and-yellow garden spider is the inspiration in spirit for Charlotte in E.B. White's 1952 Charlotte's Web (the book identifies Charlotte as a 'gray spider, scarcely larger than a gumdrop' — taxonomically, Charlotte was probably Araneus cavaticus, the barn spider, not Argiope, but the dramatic zigzag-web orb-weaver remains the cultural mental image of 'a spider that writes letters'). The species is non-aggressive and harmless to humans (mild bite if directly handled). Females are large and dramatic; males are small (5 mm), often killed and eaten after mating.