Webstruct

This project was done in the Oxford Silk Group under supervision of Prof. Fritz Vollrath and aimed to investigate how orb spiders with different energetic web-building costs adjust their building behaviour and the resultant web geometry to both changes in and predictability of environmental conditions. Specifically, I focused on two functional (biotic and abiotic) aspects of the web; its ability to capture prey and to withstand wind.

To analyse the effects of wind, orb webs were studied in a wind tunnel with the specific aim to study, whether spiders change their investment strategy in unsteady and unpredictable winds.
To analyse the effects of prey impact,cameras were used with the objective to quantify how spiders with different energetic investment strategies adapt their webs to different prey. Finally, analytical models (using finite element analysis) is used to uncover the underlying dynamics of webs during both prey impact and wind loading, with the goal to relate web-geometry with web-engineering, i.e. force distribution and energy dissipation.

This provided information on the functional importance of the various substructures in the webs in order to examine and predict the optimisation criteria for web design in specific environments. The main focus was on the mechanical role of the zigzag shaped non-sticky spiral in golden orb-weaver spiders of the genus Nephila, but the project also included investigating the role of wind on prey-capture and web-repair behaviour.

Links:
Oxford Silk Group
Department of Zoology, Oxford University

Publications:
Tew, E. R., Adamson, A. and Hesselberg, T. (2015). The web repair behaviour of an orb spider. Animal Behaviour 103, 137-146.
doi:10.1016/j.anbehav.2015.02.016

Chen, F., Hesselberg, T., Porter, D. and Vollrath, F. (2013). The impact behaviour of silk cocoons. Journal of Experimental Biology 216, 2648-2657.
doi:10.1242/jeb.082545.

Hesselberg, T. and Vollrath, F. (2012). The mechanical properties of the non-sticky spiral in Nephila orb webs (Araneae, Nephilidae). Journal of Experimental Biology215, 3362-3369.
DOI: 10.1242/​jeb.068890.

Turner, J., Vollrath, F. and Hesselberg, T. (2011). Wind speed affects prey-catching behaviour in an orb web spider. Naturwissenschaften 98, 1063-1067.
DOI: 10.1007/s00114-011-0854-4.

Further materials:
Talk about aspects of the project given at the Royal Danish Academy for Sciences and Letters (in Danish)
https://www.youtube.com/watch?v=D0GNbF7O9cs