After mating, a male Philoponella prominens spider uses hydraulic pressure to extend leg joints and fling himself away, seen here at about one-fiftieth actual speed and then at normal speed.
Zhang compares it to the start of a backstroke swimming race. Males hold the tips of their forward legs against a female’s body while they jump. The spiders then use hydraulic pressure to extend a joint in those legs, allowing them to quickly launch a male off an unsuspecting female before she can capture and eat him.
The researchers studied the mating rituals of 155 animals and discovered that 152 males survived. The three remaining ones perished as a result of their partner. Female spiders also ate all 30 male paintbrush-guarded creatures who were prevented from fleeing with a catapult.
Zhang speculates that the male orb weavers’ ability to jump may have been acquired as a defensive measure against female cannibalism. The spiders’ leap to survival is a “beautiful kinetic act.”