Assassin bugs hunt spiders by plucking the threads of spiderwebs to draw the arachnids closer. Researchers in Australia report that the vibrations mimic those generated by insects trapped in the webs — and are even at specific frequencies to avoid eliciting an aggressive response.
In a series of laboratory tests, Anne Wignall and Phillip Taylor of Macquarie University in Sydney show that the vibrations induced by Stenolemus bituberus (pictured) trigger the same behaviour from spiders as do those of some prey species. Vibrations from falling leaves elicited no response, whereas those from courting male spiders led females to adopt copulatory positions.
The assassin bugs seem to avoid producing the higher frequency vibrations generated by some prey that can trigger a dangerous high-speed approach from the spider.