Evolutionary Biomechanics lab Greifswald

@evoimec.bsky.social

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Evolutionary Biomechanics lab @unigreifswald.bsky.social | Diversity & evolution of function in biological materials and animal traits | PI @wolffspider.bsky.social

Field emission scanning elactron microcopy image showing the microscopic structure of a lower web radius of the Australian netcaster (Asianopis subrufa). The thread contains two separate strands, each of which is made of a soft silk core with fine loops of nanofibres attached to it. Upon extension, the thread initially behaves like a soft elastomer, but as soon as the fibre loops straighten they add to the load resistance of the thread, causing a mixed mechanical profile that combines elasticity with strength.
Figure showing a video still from a high speed video of a netcasting spider capturing a cricket with its elastic web held in the front legs. Left to the video still there are load-strain diagrams of different lines in the web showing that the upper lines are stiff and strong and the lower lines are highly extensible. Left to the diagrams there are scanning elactron microcopy images of the dfifferent lines, showing that the upper, stiffer lines are cables made of many parallal fibres, whereas the lower lines have a soft central core with adjoined looped fibres. The degree of looping correlates with how much the spiders post-process the silk after spinning. This way they can tailor the stiffness of each line in the web separately and create a vertical stiffness gradient throughout the whole web architecture from stiff and strong in the upper load bearing frame to soft and hyper-elastic in the lower part that is rapidly extended and thrown against the prey at high speed during the predatory strike.
Members of the EvoMec lab standing on a wooden bench on the hilltop of Dornbusch, Hiddensee Island, with lighthouse in the background.