Nephila Research Articles

Structural organization of spider silk

Spider silks are protein polymers with outstanding physical properties. A benchmark for spider silks is the dragline thread of the golden silk spider Nephila. Our study using urea super-contraction suggests a new model for the microstructure of this silk. According to this model, which challenges the general view, this silk consists of a structured fibril tube surrounding a thin core. This hypothetical structural organization could explain the supreme tensile strength of this interesting biopolymer.

Sexual cannibalism, competition, and size dimorphism in the orb-weaving spider Nephila plumipes Latreille (Araneae: Araneoidea)

The degree and direction of sexual dimorphism varies widely, but in several taxa of orb-weaving spiders, including Nephila, males may be less than one-tendi the size of females. This difference is commonly attributed to selection dirough precopulation sexual cannibalism: females may eidier fail to detect very small males, or ignore them as potential prey items. However, there is often the potential for male-male competition in these species because several males can be found on die web of a single female. We investigated experimentally the effects of sexual cannibalism and male-male competition on male body size and hence sexual dimorphism in die Australian golden orb-weaver (Nephila plumipes). Small males were less likely to be detected and cannibalized than larger males. However, larger males excluded small males from die central hub of the web, where mating takes place. The conflicting effects of sexual cannibalism and male-male competition may be responsible for die relatively large variation in male body size in diis species.

Male advantage for egg fertilization in the golden orb-weaving spider (Nephila clavipes).

Male advantage for egg fertilization in the golden orb-weaving spider (Nephila clavipes).

Male advantage for egg fertilization in the golden orb-weaving spider (Nephila clavipes).

Male advantage for egg fertilization in the golden orb-weaving spider (Nephila clavipes).

In defense of Nephila clavipes: Postmate guarding by the male golden orb-weaving spider.

In defense of Nephila clavipes: Postmate guarding by the male golden orb-weaving spider.

In defense of Nephila clavipes: Postmate guarding by the male golden orb-weaving spider.

In defense of Nephila clavipes: Postmate guarding by the male golden orb-weaving spider.

The ecology and behavior of Nephila maculata : a supplement

The ecology and behavior of Nephila maculata : a supplement

Ecology and behavior of the giant wood spider Nephila maculata (Fabricius) in New Guinea

Ecology and behavior of the giant wood spider Nephila maculata (Fabricius) in New Guinea

Photographic surveying in Canada

Measurements of optical birefringence have been used to characterise the effect of mechanical history on supramolecular structure in major ampullate silk from Nephila clavipes (golden orb weaver) spiders. Birefringence modelling is demonstrated to be a powerful technique for obtaining quantitative information on supramolecular rearrangement in response to macroscopic strain. Temporary and permanent birefringence changes measured as a function of strain and strain rate are interpreted in terms of two types of microstructural response: increased molecular alignment in all the microstructural phases present is accompanied by decreased lateral register within crystallographically ordered phases. Significant implications of these studies for the commercial processing of silks and silk-like biopolymers are discussed.