London – 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 the question of why the jumping spider evolved in the way it did.
Researchers wondered 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.
For all her agility, she does not take any risks when jumping as she ties a strand of silk to terra firma before springing off.
The researchers used cameras and high-resolution micro CT scans – a form of X-ray – to record, monitor and analyse Kim’s movement and behaviour. The scientists 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 Manchester pet shop, only Kim co-operated 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 take-off 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. However, when facing a longer distance, an elevated platform or rougher terrain, she jumps in the most efficient way to reduce the amount of energy used.
Insects and spiders jump in different ways, either using a spring-like mechanism, direct muscle forces or internal fluid pressure.
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 actively used to enhance or replace muscle force when the spiders 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."
IT SURVIVES ON ONE CRICKET A WEEK
The regal jumping spider eats just one cricket a week.
That meant that Kim had to be trained without using food as an inducement. Scientists lifted her across a gap by hand to show her what they wanted her to do.
There are more than 5 900 species of jumping spider – around 13 per cent of all spider species.
They face their prey and jump to catch them – injecting them with venom – rather than using a web.
The regal jumping spider, which has four forward-facing eyes, uses its excellent vision to stalk its prey.
It is mostly harmless to humans. While it can deliver a painful bite, it will only do so if held tightly.
It uses its silk to spin a safety line in case it misses its landing spot. It can also spin a nest to sleep in.
The species occurs in the south-eastern US and the West Indies, and has been introduced to Easter Island in the Pacific.