In an astonishing find, scientists have unravelled the mystery of some predatory spiders and how they catch their prey. Researchers studied this by teaching one predatory spider to jump at different distance and at different heights to aid the hunt. Study authors then monitored the jumps of the spider with slow-motion cameras and analysed how it uses different jumping techniques based on different situations and challenges to catch the prey.
Researchers from the University of Manchester taught the spider nicknamed “Kim” to jump at different distances and at different heights. They used one of the most advanced techniques including 3dCT scanning and high-speed, high-resolution cameras to record even slightest of the movement and behaviour of the predatory spider in different situations to kill its prey.
Scientists conducted the research to answer why such anatomy and behavioural evolution takes place the way it did. In addition, the study will also help scientists in designing highly agile and better micro-robots to aid humans in future missions.
“The focus of the present work is on the extraordinary jumping capability of these spiders. 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. The force on the legs at take-off can be up to 5 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,” said lead study author Dr Mostafa Nabawy.
For the study, researchers chose a species of jumping arachnid known as Phidippus regius, or ‘Regal Jumping Spider’. Researchers presented several manmade challenges in front of Kim. Some were close ranged distances while some were long range. They monitored each jump using high-speed cameras and created a 3D model of Kim’s legs and body structure in unprecedented detail.
Study authors found that Kim had developed its own technique to kill the prey. Kim moved faster to jump shorter and close range distances which used up more energy by reducing flight time making the jump more accurate and effective. However, to jump longer distances or to an elevated platform, Kim used a technique that minimised the energy used.
Previously, researchers knew that spiders can use internal hydraulic pressure to extend their legs but the hydraulic pressure would also enable them to jump came as a surprise to study authors.
Dr Bill Crowther, co-author of the study, explains: “Our results suggest that whilst Kim can move her legs hydraulically, she does not need the additional power from hydraulics to achieve her extraordinary jumping performance. Thus, the role of hydraulic movement in spiders remains an open question.”
The study appeared in the journal Nature Scientific Reports.