Each of the droplets that form an orb-weaving spider's viscous capture thread are composed of a viscoelastic glycoprotein glue core that is surrounded by an aqueous layer and supported by a pair of protein axial fibers. Low molecular weight organic and inorganic compounds within the aqueous layer confer droplet hygroscopicity, thereby maintaining the glycoprotein's adhesion and extensibility and ensuring that the axial fibers remain supercontracted. These materials also cause droplet volume to change in response to ambient humidity. This study examined the viscous threads of Argiope aurantia Lucas 1833, a species found in exposed, low humidity habitats, and Neoscona crucifera (Lucas 1838), a nocturnal species found in high humidity forest edge habitats. An earlier study showed the former species' threads to be more hygroscopic than those of the latter. When aged and exposed to chemical fixatives, the hygroscopicity of A. aurantia threads decreased, while that of N. crucifera threads was unaffected. Fixation eliminated the extensibility of both species' droplets. However, droplet adhesion, as measured by the deflection angle of a thread's axial lines just prior to droplet extension or, in the case of fixed droplets, droplet pull-off, was unaffected. These findings indicate that the compounds that confer greater hygroscopicity to A. aurantia viscous threads are more susceptible to chemical fixatives than those in the aqueous layer of N. crucifera droplets.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 43 • No. 2