The effects of wind disturbance on silk properties and web structures of orb-weaving spiders.
Most orb-weaving spiders use silk to construct their web to capture prey. In the orb, the silks produced by major ampullate glands serve as radius and frame to support the structure of whole web. Previous studies show that spiders can adjust the mechanical/chemical properties of spider silk/web in response to prey variation and spider biomass. However, the effects of environmental physical disturbances on these properties are still unclear. By comparing the properties of silk/web of two Cyclosa spiders inhabiting habitats of different level of wind disturbances, I investigated whether spiders would alter silk and web properties in response to such disturbance. I also manipulated wind speed in the laboratory to investigate whether such treatment will affect web/silk properties. The results showed that the major ampullate silk of C. mulmeinensis inhabiting seashores contained higher percentage of glycine and lower glutamine than those of silk from the forest-dwelling C. ginnaga. Moreover, the ultimate tension and breaking energy of major ampullate silk of C. mulmeinensis were higher than those of C. ginnaga. Results of laboratory studies showed that spiders receiving wind disturbance produced stronger major mapullate silk, although silk amino acid composition and diameter did not differ. Spiders subjecting to wind disturbance also built smaller and looser webs to reduce wind drag. These results imply that orb-web spider inhabiting areas of different level of wind disturbances exhibit variation and plasticity in silk and web properties.
Updated: Mar-10-2014 01:22:51 (Taiwan, GMT+08:00).