Predatory Behavior and Web Orientation of the Golden Orb-Weaving Spider, Nephila Clavipes Linnaeus

Predatory Behavior and Web Orientation of the Golden Orb-Weaving Spider, Nephila Clavipes Linnaeus

Alvin Sherman Library 2053

Nephila clavipes is a type of orb-weaving spider. This means that their web comprises a hub, radii, and a sticky spiral in an orb shape. Orb weavers typically have poor vision and feel vibrations in their web to detect prey. Nephila clavipes is mostly found in the southern U.S. and in tropical climates. Adult female Nephila webs are usually very large, averaging 1 m (39’’) or more in diameter. These spiders are not poisonous to humans but may seem intimidating because of the large size of the female, which varies but is about 25 mm (1”) body length. The purpose of this study was to describe their predatory behavior and web orientation. Searches were conducted in Tree Tops Park and because of their size they were spotted fairly quickly along nature paths. The date, time, location, temperature, and weather were noted first. The first measurements were done at a distance and include measuring the angle of the plane of the web with a clinometer, noting missing legs, measuring the compass direction of the dorsum, noting wrapped prey, barrier webs, Argyrodes (kleptoparasitic spiders), male Nephila, and any damage to their web. The next measurement was touching a 100Hz tuning fork to the web to simulate prey. Responses were scored 0-6 (no response to full response). Leg segments were measured as an index of size of the spider, along with how high the hub of the web was from the ground, the spiral height, and the spiral width. The results found theNephila clavipes typically have webs that face east. Their webs were found to be only slightly inclined from vertical. The response to the 100Hz tuning fork usually was an approach and bite of the fork. The tendency of the spiders to build their webs facing east may be related to thermoregulation or prey capture. The response to the 100Hz tuning fork closely resembles the Nephila response to relatively small, nonthreatening prey.