KQED recently featured ESPM graduate student Ignacio Escalante in “Deep Look," a video series that explores scientific mysteries and compelling research. Escalante, a graduate student in the Elias Lab, examines the behavioral ecology of animals. His current research focuses on daddy longlegs and how they move when they’ve lost a leg.
“They have a 60 percent probability of losing a leg during their lifetime,” Escalante explained. “It’s a very common phenomenon, so you would expect to find compensatory mechanisms.” Those mechanisms include developing different types of strides more suited to the new leg count.
After losing one leg, a daddy longleg begins to favor “stotting,” where it dribbles its body on the ground like a basketball with every stride. After losing two legs, it turns to “bobbing,” where the vertical plane of movement becomes pronounced.
“For certain variables, like speed, there’s a recovery after a few days,” said Escalante.
Because they are more chaotic, these forms of movement may even help the daddy longlegs stay alive longer because it becomes difficult for predators to track. The proof, as the saying goes, is in the pudding.
“If you have four legs, it probably means that you have successfully escaped four encounters with predators,” said Escalante.