CHAPEL HILL, N.C., May 2 (UPI) -- U.S. scientists say they have determined how certain land crabs use air and internal fluids to survive the highly vulnerable state of molting.
If otherwise healthy humans temporarily lost their skeletons, they could neither protect themselves nor move around. But millions of small animals do lose their skeletons one or more times a year in a risky process known as molting. As arthropods grow, they must shed their tough outer shells, or exoskeletons, to have room to expand.
Working at the University of North Carolina at Chapel Hill, two researchers have discovered how some land crabs survive the process by using air in combination with internal fluids to increase pressure inside their bodies.
The higher internal forces create temporary turgidity and the crabs employ that pressure to move their legs and claws for several days until their newly secreted larger shells harden. After that, their exoskeletons can, in the usual way, resist muscle contractions, which thereby produce movement, the researchers said.
A report on the study by doctoral student Jennifer Taylor and her mentor, Professor William Kier, appears in the April 20 issue of the journal Nature.
