London, June 28 : Black widow spiders spin a deadlier web when they are hungry, and a fortress to have a better protection from predators when they are sated with food, according to a new study.
Conducted by Jacquelyn Zevenbergen and Todd Blackledge at the University of Akron in Ohio, the study showed that the spiders fed daily with crickets spun tangled masses of non-sticky silk.
The researchers also found that similar-size spiders, when starved for a week, tended to spin sheets of silk connected to the ground by taut, sticky strands.
They say that such webs detach from the ground when an insect blunders into their strands, and sprig upwards, suspending the prey in mid-air.
The sheet-like webs are better at transmitting the vibrations of passing prey, and also make it easier for the spider to manoeuvre.
During the study, it was observed that all spiders, irrespective of their condition, caught more prey more quickly and efficiently when they placed them on the webs spun by hungry individuals.
Blackledge said that the sated spiders opted to spin tangled, non-sticky webs because they could provide better protection from predators.
The researcher said that such a purposeful alteration to web design was unique to black widows.
"Their webs aren't simply more or less of the same thing. They are adding and deleting architectural features that have specific functions," New Scientist magazine quoted him as saying.