Effect of wind on properties of silks and sticky droplets produced by Cyclosa mulmeinensis

• Main Authors: Chao-Chia Wu, 吳兆佳
• Other Authors: Sheng-Hai Wu
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/03045194298101454698

碩士 === 國立中興大學 === 生命科學系所 === 100 === The orb weaving spider can alter web properties in response to different environment factors. Previous studies showed that the dust spider Cyclosa mulmeinensis could build the webs with smaller catching area, larger mesh height and stronger major ampullate silks under windy conditions. I hypothesized that C. mulmeinensis under wind disturbance condition would build sticky spirals with more and larger sticky droplets to increase stickiness and decrease sticky droplet surface area to volume ratio to decrease water evaporation. I also hypothesized that a stronger MA silks might be generated by changes in silk amino acids or crystallization. To test these hypotheses, I subjected C. mulmeinensis to wind-disturbance and control treatments and measured silk/web properties and sticky droplet features. Moreover, I also measured the silk chemical and mechanical properties. The results showed that the mechanical properties of the MA silks were enhanced under wind disturbance condition but the amino acid compositions did not change. On the other hand, C. mulmeinensis under wind disturbance conditions produced sticky droplets with larger size and smaller surface area to volume ratio but the stickiness remained the same. Such results suggest that under wind condition spiders might behaviorally adjust droplet feature to reduce evaporation and to maintain stickiness.