London, May 8: Scientists have successfully trained a spider to jump different distances and heights for the first time, unlocking the secrets of how some predatory species catch their prey while hunting. The study by researchers at the University of Manchester in the UK is the most advanced of its kind to date and first to use three-dimensional (3D) CT scanning and high-speed, high-resolution cameras to record, monitor and analyse a spider's movement and behaviour. The aim of the research, published in the journal Nature Scientific Reports, is to answer the question of why jumping spider anatomy and behaviour evolved the way it did.
This improved understanding of spiders will help imagine a new class of agile micro-robots that are currently unthinkable using today's engineering technologies, researchers said. "The focus of the present work is on the extraordinary jumping capability of these spiders," said Mostafa Nabawy, lead author of the study. "A jumping spider can leap up to six times its body length from a standing start. The best a human can achieve is about 1.5 body lengths," said Nabawy. "The force on the legs at take-off can be up to five times the weight of the spider - this is amazing and if we can understand these biomechanics we can apply them to other areas of research," he said.
The researchers trained the spider, which they nicknamed Kim, to jump different heights and distances on a manmade platform in a laboratory environment. Kim belongs to a species of jumping arachnid known as Phidippus regius, or 'Regal Jumping Spider'. The team then recorded the jumps using ultra-high-speed cameras, and used high resolution micro CT scans to create a 3D model of Kim's legs and body structure in unprecedented detail.
The results show that this particular species of spider uses different jumping strategies depending on the jumping challenge it is presented with. For example, to jump shorter, close-range distances Kim favoured a faster, lower trajectory which uses up more energy, but minimises flight time. This makes the jump more accurate and more effective for capturing its prey. However, if Kim is jumping a longer distance or to an elevated platform, perhaps to traverse rough terrain, she jumps in the most efficient way to reduce the amount of energy used. Insects and spiders jump in a number of different ways, either using a spring like mechanism, direct muscle forces or using internal fluid pressure.