Researchers from the University of Bristol’s School of Biological Sciences wanted to discover how the crabs switch from hypoactivity to hyperactivity in order to carry out this remarkable athletic feat with no training.
Professor Steve Morris and colleagues carried out genetic analysis on samples of leg muscles from the crabs during their migration journey and sixth months afterwards. They found that the crabs made major physiological changes to their muscle composition over a very short time to sustain aerobic high-endurance muscle for their trek to the coast.
By examining the versions of genes that were expressed, the team could see that for most of the year, the crabs’ muscles were tuned only for short sprints. However, when the monsoon arrived, the crabs’ muscles underwent a dramatic change, becoming aerobic and highly resistant to fatigue. This allowed the crabs to be on the move for up to 12 hours a day during their monsoon season trek to the coast compared with an average of just 10 minutes during the dry season when they remain mostly inactive in their inland burrows.
Tragically, Professor Morris did not live to see this research published as he was killed in a traffic accident in August 2009.
His colleague, Professor Mark Viney, said: ”Steve was a traditional physiologist and this was the first time that he had done a study at the molecular level. It was a brave new departure for him and this paper is the first manifestation of this new direction of his research. Steve never let anything stop him and we took that spirit on to get this paper out.”
The research was supported by a Faculty of Science research bursary from the University of Bristol, and funded in part by a Natural Environment Research Council (NERC) grant. It is published in the May issue of The Journal of Experimental Biology.