Male blue-lined octopuses inject females with venom throughout intercourse, paralysing their bigger mates to keep away from being eaten, new analysis has discovered.
The blue-lined octopus is a tiny, extremely harmful cephalopod discovered generally in shallow reefs and tide swimming pools.
One of many 4 species of blue-ringed octopus, it makes use of an especially potent neurotoxin referred to as tetrodotoxin – additionally present in pufferfish – to immobilise its prey.
A brand new examine means that male blue-lined octopuses use a exact chunk to inject the venom into the feminine’s aorta originally of mating.
Full-sized females are in regards to the measurement of a golf ball – round two to 5 occasions larger than their male counterparts – in response to the examine’s lead creator, Dr Wen-Sung Chung of the College of Queensland.
Feminine octopuses are liable to consuming their mates, he stated.
“Sexual cannibalism is quite common in cephalopods.
“When feminine blue-lined octopuses lay eggs, they spend roughly six weeks with out feeding simply taking care of the eggs. They actually need numerous power to get them by that brooding course of.”
Male octopuses have a specialised arm for mating – generally known as the hectocotylus – which transfers a sperm capsule into the feminine’s oviduct.
Males have developed distinct methods to keep away from falling prey to their mates throughout copulation: the argonauts, for instance, sacrifice their mating arm and let it drop off after mating. Different species have an elongated hectocotylus.
“The blue-lined octopus’s mating arm is way shorter,” Chung stated. “Unable to do long-distance mating, they should do a mounting mating technique.”
The researchers noticed male octopuses immobilising females throughout mating classes that lasted between 40 and 75 minutes. Because the tetrodotoxin took impact, the females stopped respiration after about eight minutes, turning pale and their pupils not responding to mild.
“Mating ended when the females regained management of their arms and pushed the males off,” the scientists famous.
Not one of the females died throughout copulation, they usually fed usually the next day, suggesting resistance to tetrodotoxin, Chung stated.
Envenomation by blue-lined octopuses may be lethal to people; deadly instances have additionally been documented in inexperienced sea turtles in Moreton Bay, who by chance ingested the octopuses whereas consuming seagrass.
Blue-lined octopuses, like most octopus species, exhibit semelparity, a breeding technique wherein an organism dies after it reproduces as soon as. The males die quickly after copulation, whereas the females die after their larvae hatch.
Chung referred to as the weird mating method in blue-lined octopuses an evolutionary “arms race” between the 2 sexes.
“As a result of the females grew to become a lot larger and stronger … the male finally wanted to have a selected technique to verify his genes may be transferred to the subsequent era.”
The analysis was printed within the journal Present Biology.
Supply hyperlink
