Spider orb webs are semi-permanent records of foraging behaviour making them ideal to examine the interaction of environmental conditions and behavioural decisions. The spider adjusts the detailed geometry of the web to a wide range of factors in order to tune the primary function of the web, prey-capture, while at the same time ensuring its structural integrity. Here I propose to study how orb spiders adapt their webs to the stability of the environment. Spiders that invest more are expected to be better in tuning web structure to match environmental conditions and are expected to show more complex adjustments in web-geometry to unpredictability than low investment spiders. Four goals will be pursued: (i) Comparative examination of the energetic costs of web-building for three ecribellate and one cribellate orb weaver using rather different web-silk integration. The cost of web-building is known to significantly higher than the material costs. (ii) Analysis of the effect of web costs on the adaptability to prey type and (iii) of the effect of web cost on the adaptability to wind-loading and wind predictability. The geometry of the orb and the web-building behaviour are both expected to depend on the predictability of the environment (iv) The use of finite element models in order to analyse prey impacts and wind-loading both as separate and integrated effects. The results are expected to be of considerable interest for both the design of biomimetically inspired light weight structures and the analysis of animal decision making.
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