A spider named Kim is helping scientists create agile jumping robots. Using high-speed cameras and 3D CT scans, researchers from the University of Manchester recorded how Kim jumps to capture the mechanics and the minutest details of how spiders leap.
The study is now published in Nature Scientific Reports. The researchers hope that their improved understanding of spiders’ jumping mechanisms will help create a new class of agile micro-robots using today’s engineering technologies.
This is not the first study to examine jumping spiders in a laboratory setting, but this is the first to capture how spiders leap in such detail and with varying distances and heights.
And that’s not the most amazing part.
The key to the study’s success in capturing spider jumps in detail is that they specifically trained regal jumping spiders to jump from platform to platform. The team started with four female regal jumping spiders (Phidippis regius), but only one spider was willing to jump on demand – and that was Kim.
Training Spiders to Jump on Demand
Lead author Dr. Mostafa Nabawy specifically chose spiders for their unique jumping behavior. Unlike other insects who jump to escape predators, spiders jump to catch their prey. Exhibiting intelligence in assessing their surroundings and planning how to capture their prey, spiders make for interesting subjects.
Contrary to what most would expect, the researchers did not train the spiders with treats or baits. Since spiders only subsist on one bug per week, they cannot be lured to jump with prey all the time.
To train the spiders to jump on demand, the researchers transferred them from one platform to another. Training the other spiders was not successful, but Kim showed great promise.
In a week, Kim made 15 jumps both level and uneven. She also performed well in jumping from a lower platform to a higher one and vice-versa. From Kim’s jumps, cameras were able to capture how Kim readjusted her strategy according to the height and distance of the platform she has to leap to.
What Kim’s Jumps Have Revealed
Recordings of Kim’s jumps have revealed how she oddly exerts more effort for short jumps (around twice her 1.5 cm body). The farther or higher the jump required of her (as far as five times her body length), however, the less energy Kim used.
The researchers believe that the short fast jumps that Kim exhibited are what jumping spiders use to catch their prey. The researchers also saw that, unlike other jumping spiders who used their silk to help them steady themselves during a jump, Kim uses the silk as a safety line in case she fails to reach the other platform.
Of course, from knowledge gleaned from Kim, more questions surfaced.
From previous studies, scientists speculated that spiders use internal hydraulic pressure to propel themselves forward. Kim, however, seemed to use muscle power alone. According to Dr. Nabawy, they found that Kim’s estimated muscle power is sufficient to power the jump. This suggests that hydraulic augmentation may be present but not essential as an energy source.
Dr. Nabawy’s team believes that more sensitive experiments might reveal that jumping spiders use both techniques depending on the situation.
For now, let’s forget how scary spiders can be and enjoy the sight of Kim gracefully jumping distances five times her body length.