Life for an orb-weaver spider is a balancing act.
Cyclosa ginnaganeeds to attract tasty insect
prey, while evading wasps, its main predator.
“It is playing a delicate game,” says Dr Sara
Goodacre of the University of Nottingham’s
SpiderLab. “Does it prioritise dinner, or
defence?” The spider adds a special kind of
backcombed silk to its web to imitate splattered
bird poo, and this, experiments show, attracts
more poo-loving prey, such as flies. It also
incorporates bits of leaf and twig, with the same
effect. Other experiments have tested whether
this technique is a defence, by blackening
individual spiders or their webs. They found
that darkened (and therefore more visible)
spiders were indeed more likely to be attacked,
possibly because they looked less like poo.
So is this spider using poo mimicry for prey
attraction, predator defence, or both? The jury’s
out. But you can’t deny that it’s a talented artist.�WEB OF DECEPTION