Eight-Legged Candy-Striper Killers Prowl Before the Sun Rises

They also engineered predatory opportunities, introducing spiders to the base of vegetation where insects were sleeping topside. Sure enough, spiders, sensing slow food, climbed stalks to do their deeds. Even without human transport, however, candy-striped spiders were observed ballooning and rappelling between insect bedrooms, surreptitiously securing sleeping targets with sticky silk.

Candy-striped spiders are not choosy about what they eat, preying on about 250 species, mainly bees and wasps. Nighttime forays are cleverly timed, Dr. Scott explains. Prey species are relatively well defended during the day but “rather helpless at night,” she says, because it takes time for a sleeping insect to rouse enough to defend itself.

Spider hunting habits are incredibly diverse, ranging from familiar sticky webs to webless ambushing of prey beyond insects, including fish, bats, birds and other spiders. But Dinesh Rao, an arachnologist at the University of Veracruz in Mexico, who was not involved in the study, finds this newly discovered behavior surprising, suspecting it is a response to the abundance of sleeping insects.

We know very little about the behavior of the vast majority of the 50,000 spider species named to date, Dr. Rao adds. “While there are a handful that are well studied,” he said, “we lack basic behavioral knowledge of most spiders.”

Dr. Scott and Dr. McCann say this new discovery underlines the importance of taking time to be curious and “simply watch,” something modern ecologists rarely do, they argue. It took almost 100 years before anyone reported the remarkable marauding behavior of these extremely common species, prompting them to wonder how many other spider mysteries are yet unspun.