A research group from the University of Tokyo and others has announced the results of a study showing that the ink that squids spit out to confuse their enemies and escape is also used in courtship behavior to make themselves stand out in white and appeal to females.
This is the first time that such courtship behavior has been confirmed, and the research group hopes that it will be useful in understanding the evolution of animal communication.
A research group led by Arata Nakayama, a graduate student at the University of Tokyo, noticed that when males of the cuttlefish, the cuttlefish, spit out ink while courting females, they touched each other with two special arms. I did it.
As a result, the male strokes the female with his arm for a long time and spits out small lumps of ink, and then finally spits out ink over a wide area, darkening the background, making his body shine white, and attracting the female. It has been revealed that they are courting.
According to the research group, this is the first time that a squid that engages in such courtship behavior has been observed.
Associate Professor Yoko Iwata of the University of Tokyo's Atmosphere and Ocean Research Institute, a member of the research group, said, ``I was very surprised to find that highly intelligent squids divert the ink they normally use for escape to courtship behavior. "Being able to set the stage for this is a huge benefit and will help us understand the evolution of animal communication."
Courtship with the “heart mark”
The ``Ezohari squid'' is a small squid with a body length of about 12 centimeters and lives in the sea from southern Hokkaido to the Philippines at a depth of about 50 meters, but its detailed ecology is still poorly understood.
In 2019, the Aomori Prefectural Asamushi Aquarium, which is said to be the first in Japan to successfully breed this ``Ezoharika'' squid, captured a scene in which a male is said to be courting a female while making a ``heart mark'' with its two short arms. It was successfully photographed and became a hot topic.
The results of this research were made possible through continued observation, paying attention to the fact that while making a "heart mark" with their arms, they were also spitting out ink at the same time.