All tangled up - spiders hunt heavy prey using a pulley system
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Publicly released:
2021-02-03 11:01
Many species of tangle-web spiders - a family which includes the Australian redback spider - are able to use 'pulleys' of pre-stretched silk to capture prey 50-times heavier than themselves, according to international research. The team observed how spiders would ensnare beetles of varying size, using a series of silk 'pulleys' to hoist the prey into the air, and tracked how efficiently they were lifted. The researchers note that this style of hunting allows the spiders to capture prey as large as lizards and small mammals, which would be impossible using muscle strength alone.
Journal/conference: Royal Society Interface
Link to research (DOI): 10.1098/rsif.2020.0907
Organisation/s: University of Trento, Italy
Funder: N.M.P. is supported by the European Commission under the FET Proactive (Neurofibres) grant no. 732344, the FET Open (Boheme) grant no. 863179 as well as by the Italian Ministry of Education, University and Research (MIUR) under the ‘Departments of Excellence’ grant L. 232/2016, the ARS01- 01384-PROSCAN and the PRIN-20177TTP3S grants. G.G. is supported by this last grant.
Media release
From: The Royal Society
Deadlift - Tangle-web spiders can use “pulleys” of pre-stretched silk to capture prey 50-times heavier than themselves, by hoisting them into the air. In the first laboratory study of the mechanics of ‘lifting hunting’ researchers tested the spiders ensnaring beetles of varying size and tracked how efficiently they were lifted. The authors note this ingenious use of silk allows the spider to hunt ‘peculiarly large’ prey, including lizards and small mammals, which would be impossible using muscle strength alone. (Photos and videos available)
The spiders of the Theridiidae’s family display a peculiar behaviour when they hunt extremely large prey. They lift the quarry, making it unable to escape, by attaching pre-tensioned silk threads to it. The cobweb of these spiders, thus, is used as a pulley to overcome their muscles limits.
We thus report here further evidence for the strong role of silk in spiders’ evolution, especially how spiders can stretch and use it as an external tool to overcome their muscles’ limits and capture prey with large mass.
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