How Daddy-Longlegs Catch the Uncatchable

Daddy-longlegs have proven to be expert hunters, literally snatching fleeing prey out of the air. Now, researchers have taken a close look at how exactly these creatures developed their unique hunting style, seemingly adapting to catch one slippery prey in particular.

Not to be confused with the spindly basement-dwelling daddy-longlegs spider (Holocnemus pluchei), the true daddy-longlegs (Mitostoma chrysomelas) - also called "harvestmen" - are not spiders. Of the Order called Opiliones, harvestmen are eight-legged arachnids that boast one basic body segment and two eyes at-most.

They don't spin webs, but instead hunt the ground and air of deciduous woodland with a pair of specialized arms that can snatch up any prey smaller than it.

According to a study recently published in the Journal of Experimental Biology, these hunting arms are called pedipalps, and may have even been adapted to catch one type of prey in particular, called springtails.

Collembolla, commonly referred to as "springtails," are one of the most abundant insects in the world. Turn over the compost heap in your garden and you may notice these tiny buggers frantically hopping away. They have even been seen to amass in huge swarms on the surface of fresh snow, and are often referred to as "snow fleas." Interestingly, these insects aren't hopping away on their legs.

They try to escape predators using their furca, a naturally loaded spring located on their abdomen - their namesake. This makes them particularly difficult to catch, as they can spring away from predators at the first hint of danger.

Or they would, if it were not for the daddy-longlegs' sticky arms. A close analysis of huntsmen pedipalps has revealed that they are lined with hair covered in a sticky, superglue-like liquid.

"It behaves more like a solid under high stress rates," study author Jonas Wolff recently explained to New Scientist. "The faster the prey moves, the stronger the bonding is within the glue."

When huntsmen unearth a spingtail, they tend to catch the insect mid-jump, snaring it out of the air with their sticky whip-like arms.

Interestingly, the springtail is not without its own defense. According to Wolff, the tiny insects are covered in specialized cuticles that repel liquid. This could save the insects from getting stuck in damp soil, but it also makes them harder to grab - sticky whips or not.