Scientists
train spider to jump on demand
Jordan Kenny, University of Manchester (UK)
To watch this video on YouTube: https://www.youtube.com/watch?v=C6PAClh1IZo
Scientists have unlocked the secrets
of how some predatory spiders catch their prey whilst hunting by successfully
training one to jump different distances and heights for the first time.
The study, conducted by researchers
at *The University of Manchester, is the most advanced of its kind to date and
first to use 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 is to answer
the question of why jumping spider anatomy and behaviour evolved the way it
did, and secondly, to use this improved understanding of spiders to imagine a
new class of agile micro-robots that are currently unthinkable using today’s
engineering technologies.
Dr Mostafa Nabawy, lead author of
the study, says: “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.”
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.
But,
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.
Scientists
have known for more than 50 years that spiders use internal hydraulic pressure
to extend their legs, but what isn’t 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, 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
research team is comprised of specialists in microsystems, robotics,
biomechanics and spider physiology from the University’s School of Mechanical, Aerospace and
Civil Engineering and School of Earth and Environmental
Sciences. These were Dr Mostafa Nabawy, Dr Girupakaran
Sivalingam, Dr Russell Garwood, Dr William Crowther and Prof William Sellers
Reference: The
paper, 'Energy and time optimal trajectories in exploratory jumps of
the spider Phidippus regius' is being published in the journal Nature Scientific Reports by Mostafa
R. A. Nabawy, Girupakaran Sivalingam1, Russell J. Garwood, William J. Crowther
& William I. Sellers DOI:10.1038/s41598-018-25227-9
