Toxic Love

For male blue-lined octopuses, love is a dangerous game – one that often ends in the male becoming a post-coital snack.

As a result, these tiny cephalopods have developed a shocking survival strategy: Paralyzing their mates in the middle of mating with a powerful neurotoxin to avoid being eaten.

Sexual cannibalism is common among cephalopods because female octopuses need a big feast to produce and incubate their eggs.

“When female blue-lined octopuses lay eggs, they spend roughly six weeks without feeding just looking after the eggs,” lead author Wen-Sung Chung told the Guardian. “They really need a lot of energy to get them through that brooding process.”

In many octopus species, males have evolved longer mating arms to stay at a safe distance or even detachable sperm-delivery appendages – as seen in argonauts.

But blue-lined octopuses have no such luxury and rely on a paralyzing bite.

In their paper, the research team filmed the octopuses mating and noticed how the males would mount females from behind and deliver a precise bite to the aorta, injecting them with tetrodotoxin (TTX) directly into their circulatory system.

Within minutes, the females became unresponsive, their breathing slowed, and their pupils stopped reacting to light.

“They have very strange mating behavior,” Chung told CNN.

The paralysis lasted for about an hour, just long enough for the male to complete mating and make his escape. Once the toxin wore off, the females regained control, but they remained too weak to turn their mates into a final meal.

Interestingly, none of the females died from the venom, suggesting they have some resistance to TTX.

The findings could explain why male, blue-lined octopuses have evolved unusually large venom glands despite their small size.

Chung suggested that this behavior represents an evolutionary “arms race” between the sexes, with males developing a way to pass on their genes without becoming dinner.

While this discovery sheds new light on octopuses’ method of reproduction, it also highlights the sheer brutality of nature.

“It’s a kind of survival skill,” Chung told CNN.

Correction: In Tuesday’s THE WORLD, BRIEFLY section, we said in our “No Welcome Mat: Greenlanders Criticize US Trip to the Island” item that Greenlanders protested outside the US Embassy in Greenland’s capital of Nuuk. It is, in fact, a US Consulate. We apologize for the error.