Male Blue-Lined Octopuses Paralyze Females to Mate

Female black widows sometimes eat their mates after copulation. Female praying mantises are known for biting off the male's head. Scientists now say male blue-lined octopuses avoid a similar fate because of an aggressive defensive measure: They bite the larger females and inject them with venom near the aorta as they begin mating to paralyze them and avoid being eaten. And it's not just any venom: the neurotoxin in question is tetrodotoxin, the same one found in pufferfish. Lead study author Wen-Sung Chung of the University of Queensland tells the Guardian while the females are only golf-ball size, they're as many as two to five times bigger than the males.

Phys.org reports the researchers captured a number of the octopuses, observed them mate, and recorded their vital signs. In their study published in Current Biology, the researchers say that after the males dole out the "high-precision bite," the mating sessions typically last 40 to 75 minutes and end "when the females regained control of their arms and pushed the males off." During the period when the tetrodotoxin took hold, the females stopped and turned pale, and their pupils stopped responding to light. However, none died, and all ate normally the following day, suggesting a resistance to tetrodotoxin, per Chung. (More discoveries stories.)