When stalking web-building spiders, "Portia" try to make different patterns of vibrations in the web that aggressively mimic the struggle of a trapped insect or the courtship signals of a male spider, repeating any pattern that induces the intended prey to move towards the "Portia". "Portia fimbriata" has been observed to perform vibratory behavior for three days until the victim decided to investigate. They time invasions of webs to coincide with light breezes that blur the vibrations that their approach causes in the target's web; and they back off if the intended victim responds belligerently. Other jumping spiders take detours, but "Portia" is unusual in its readiness to use long detours that break visual contact.