Obscure Knowledge: The Trickiest Trap in Nature

How a decorative web catches more flies

Trickiest Trap
Alan/Dianne Page

Most spider webs work through chance: The spider erects an invisible trap and waits until some unlucky insect hits it. But a common Australian spider called the St. Andrew's Cross—known for its striking, cross-barred web—is sneakier.

According to Dieter Hochuli, a professor at the University of Sydney, the spider lures its prey with the highly visible white stripes of its web. The decorations, which significantly increase the rate at which it captures bees, wasps and houseflies, mimic the ultraviolet light reflected by flowers, tricking the pollinating insects into approaching the deadly trap.

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