Kim, the super spider who learned to leap on command
THE science world is set for a major leap forward… thanks to a spider called Kim who has been trained to jump on demand.
The creature – who, like her namesake Kim Kardashian, has a generously proportioned derriere – is able to jump up to six times her body length from a standing start.
Researchers examined her technique as they hope to build micro-robots that can emulate jumping spiders. One possible use would be for pest control on crops.
Their subject Kim is a regal jumping spider, or Phidippus regius – a species famed for its jumping ability.
She is just under half an inch long, but scientists from Manchester University were able to capture these remarkable images of Kim’s leaps using high-speed, high-resolution cameras. The team say their experiment explains how some predatory spiders catch their prey while hunting.
The study aimed to answer whether the spiders used their own muscle power or sprang forward using a form of hydraulics – pumping liquid into their legs to give themselves a powerful start.
The scientists said that although Kim is able to use this hydraulic technique, her muscles are quite powerful enough to propel her across large gaps.
The researchers used cameras and highresolution micro CT scans – a form of X-ray – to record, monitor and analyse Kim’s movement and behaviour.
They trained her to leap on demand by presenting her with a series of gaps to jump, lifting her across manually at first before she learned to perform the task on her own. Of four female spiders bought from a Man-
chester pet shop, only Kim cooperated with her trainers.
Dr Mostafa nabawy, lead author of the study, said: ‘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 one-and-a-half body lengths.
‘The force on the legs at takeoff can be up to five times the weight of the spider.’
The results, published in the journal nature Scientific reports, show that Kim’s species uses different jumping strategies depending on the challenge it faces.
For example, to jump shorter 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.
But when facing a longer distance or a jump to an elevated platform, she leapt in the most efficient way to cut energy use.
Scientists have known for more than 50 years that spiders use internal hydraulic pressure to extend their legs, but what is not known is if this hydraulic pressure is used when they jump.
Dr Bill Crowther, co-author of the study, said: ‘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.’