(Press-News.org) It might be hard to imagine, but dropping a limb or two is routine for spiders. If moulting goes wrong or a leg gets stuck, the pragmatic arachnids simply detach the limb just beyond the body joint. Then it regrows within a month when they are young. But how do impaired spiders cope when suddenly relieved of a couple of limbs? Capturing dinner and evading predators could become an issue. However, going down from eight to six legs might not be a problem if spiders are adaptable. Maybe they relearn how to manoeuvre on just six legs and get better at recovering after losing limbs multiple times; some insects are even capable of trotting on fewer limbs immediately after the loss. Curious to find out, Tonia Hsieh, Brooke Quinn and Sarah Xi (Temple University, USA) investigated how well Guatemalan tiger rump tarantula (Davus pentaloris) spiderlings recover their mobility when relieved of two limbs. Publishing their research in Journal of Experimental Biology, Hsieh and colleagues reveal that tarantulas do not relearn how to run after losing limbs. Instead they mix up a combination of different walking styles to compensate and run as fast as they did before losing their limbs.
Quinn and Xi gently adhered the front right and rear left legs to a piece of card, waited for the young tarantulas to detach their limbs and then filmed the animals immediately from above, capturing every detail of the arachnids’ footwork as they scampered away. Then they allowed the animals to regrow their limbs, filming them running with eight intact limbs, before encouraging the tarantulas to shed their limbs once more and filming their manoeuvres again. But with over 43,000 movie frames and more than 800 strides to analyse, Hsieh needed help to get to the bottom of what the tarantulas were up to, so she teamed up with physicists Suzanne Amador Kane and Kris Wu from Haverford College, USA, and mathematician Michael Ochs from The College of New Jersey. ‘Suzanne is an incredible out-of-the-box thinker’, says Hsieh, adding, ‘I don’t know of anyone else who could have come up with the novel approach for this analysis and then written up code to execute it’.
Immediately after losing their limbs the tarantulas seemed to pick up running as fast as they had before, which was impressive. In addition, they recovered the ability just as quickly after the second amputation, so they weren’t learning how to run on just six legs better after the second loss. Apart from splaying their legs wider, twisting their bodies a little more to one side and weaving increasingly, they were still as mobile. However, when Amador Kane, Wu and Ochs took a close look at the spiders’ footwork, it was evident that the arachnids are remarkably adaptable.
Hsieh explains that spiders with a full set of legs should alternate between having four feet (the first and third on one side, the second and fourth on the other) in contact with the ground at any one time. And six-legged tarantulas should, in theory, have two options: alternating between having four and two legs in contact with the ground – as if limping when on two alone – or alternating between using three legs touching the floor at a time, like an ant. In practice, the spiders rarely followed these rules. Tarantulas with all eight legs sometimes left a leg lingering on the ground as the next four descended, or raised the fourth limb early, leaving just three in contact. The spiders that were down two legs alternated randomly between limping forward on two and running like an ant on sets of three legs to keep moving fast. And the tarantulas seemed to favour their hind legs, which are mainly used for propulsion, keeping them grounded for longer when down to six limbs.
So, tarantulas don’t relearn how to run after losing limbs, and they bend the rules – alternating between limping and running like ants – to continue scampering without missing a beat.
***********************
IF REPORTING THIS STORY, PLEASE MENTION JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: https://journals.biologists.com/jeb/article-lookup/doi/10.1242/jeb.250243
The research article is freely available at https://journals.biologists.com/jeb/article-lookup/doi/10.1242/jeb.250243
REFERENCE: Kane, S. A., Quinn, B. L., Wu, X. K., Xi, S. Y., Ochs, M. F. and Hsieh, S. T. (2025). Unsupervised learning reveals rapid gait adaptation after leg loss and regrowth in spiders. J. Exp. Biol. 228, jeb250243. doi:10.1242/jeb.250243
DOI: 10.1242/jeb.250243
This article is posted on this site to give access to other authorised media who may wish to report on this story. Full attribution is required and if reporting online a link to https://journals.biologists.com/jeb is also required. The story posted here is COPYRIGHTED. Advance permission is required before any and every reproduction of each article in full from permissions@biologists.com.
END
For the first time, a research team led by Markus Koch from the Institute of Experimental Physics at Graz University of Technology (TU Graz) has tracked in real time how individual atoms combine to form a cluster and which processes are involved. To achieve this, the researchers first isolated magnesium atoms using superfluid helium and then used a laser pulse to trigger the formation process. The researchers were able to observe this cluster formation and the involved energy transfer between individual atoms with a temporal ...
Six out of ten people with type 2 diabetes had fatty liver in a new study from Linköping University. Of these, only a small percentage had developed more severe liver disease. The study, published in the Journal of Internal Medicine, also helps confirm that those who have type 2 diabetes in combination with obesity are at greater risk of fatty liver leading to more severe liver disease.
When metabolism does not work normally, as with so-called metabolic syndrome, many organs in the body are affected.
“Metabolic syndrome is a combination of factors leading to the body accumulating fat and not managing blood sugar levels in a good way. This entails an increased risk of developing ...
A new study from the Stockholm School of Economics finds that the competitiveness of green steel production in Romania partly hinges on hydrogen sourcing—requiring a 15 percent price premium if hydrogen is purchased externally as supposed to produced on-site. Without this premium, decarbonizing the country’s only primary steel producer could result in billions of losses.
The research, published in the Journal of Industrial Ecology, evaluates the financial viability of Liberty Steel Galați’s transition to low-carbon steelmaking using green hydrogen and electric arc furnace-based technologies. The plant, one of the EU’s top 10 most polluting steel facilities, aims ...
According to the first-ever survey fielded to RAND’s new American Youth Panel (AYP), 49% of students in middle and high school grades reported losing interest in math about half or more of the time, and 75% of youths reported losing interest for at least some class time.
Loss of interest in math is consistent across genders and racial and ethnic groups.
In the fall of 2024, RAND asked youths in grades 5 through 12 about their math class experiences with plans to measure these math attitudes annually to track trends over time. This nationally representative report was fielded to a group of ...
The Hebrew University of Jerusalem proudly congratulates three of its esteemed researchers – Prof. Dorit Aharonov, Prof. Israel Nelken, and Prof. Tamar Ziegler – on being awarded the highly competitive European Research Council (ERC) Advanced Grants.
This prestigious recognition, part of the EU’s Horizon Europe programme, supports senior researchers in pursuing ambitious, curiosity-driven projects with the potential to make significant scientific breakthroughs. The ERC Advanced Grant competition is one of ...
Amid concerns over rising petroleum prices and resource depletion, organic compounds such as methanol are attracting attention as potential replacements. Though this bodes well in theory, the production of raw materials from methanol relies on costly chemical processes. An energy-saving, bio-based process is necessary for fully tapping into this resource.
To make this a reality, Associate Professor Ryosuke Yamada’s team at Osaka Metropolitan University’s Graduate School of Engineering has developed a Komagataella phaffii (K. phaffii) yeast strain that can efficiently produce D-lactic acid, a raw material for ...
Cellulose-based textile material can make the clothing sector more sustainable. Currently, cellulose-based textiles are mainly made from wood, but a study headed by researchers from Chalmers University of Technology points to the possibility of using agricultural waste from wheat and oat. The method is easier and requires fewer chemicals than manufacturing forest-based cellulose, and can enhance the value of waste products from agriculture.
Making clothing from water-intensive cotton has a major impact on the climate. That’s why cellulose from other raw materials has come into focus in recent years as a more resource-smart method of textile production. Up to now, the ...
Melbourne, Victoria, Australia, 17 June 2025 - In a comprehensive Genomic Press Innovators & Ideas interview, Dr. Claire J. Foldi, an Associate Professor in the Department of Physiology at Monash University, shares her journey and groundbreaking work in the field of eating disorders. Dr. Foldi's research focuses on the neurobiology of eating disorders, particularly anorexia nervosa, and explores how novel therapeutics, including psychedelics, may offer new avenues for treatment.
Early Inspirations and Career Trajectory
Dr. Foldi's fascination with human behavior and the brain's processing of experiences began during her undergraduate studies. A pivotal moment ...
Would you like living next door to a solar farm? Traditionally, it’s been thought that although people like the idea of renewable energy plants, they don’t want them close by. Now research investigating how people who live near large-scale solar projects feel about them has found that 82% of people living within an hour’s walk of current projects would support, or are neutral towards, new projects in their area.
“Most neighbors of existing large-scale solar projects either support or feel neutral about additional ...
Dr. Seunggun Yu and his team at KERI's Insulation Materials Research Center have developed a groundbreaking ‘Hybrid Supraparticle Synthesis Technology’ that can attach inorganic nanoparticles to the surface of polymer microparticles through simple mechanical collisions.
The ‘Hybrid Supraparticle Synthesis Technology’ that combines functional inorganic nanoparticles with polymer microparticles is being widely applied across various industries, including battery electrode materials, catalyst systems, pharmaceuticals and biotechnology, semiconductor packaging, and insulating ...
