Squids are very mysterious cephalopods. Earlier we wrote that they are even able to edit their own genes. However, they were never considered highly loving parents, especially males. Scientists were convinced that they only mate and fight, so their strategy of behavior is quite simple. Since males of this species compete aggressively for females, after mating they stay close to their partner in order to keep other males away from her. When the female is ready to lay fertilized eggs, she looks for a secluded place among the corals, protected from currents and predators. When a suitable place is found, the female uses it repeatedly for laying. The male continues to be near her for some time even after the eggs are laid. But then he leaves her, as scientists suggest, in search of a new female. As a result, marriage history repeats itself. However, biologists recently discovered that the relationship between a male and a female can be more complex. Moreover, male reef squid are even able to show signs of paternal concern, which really amazed scientists.
Male squid take care of eggs and female
An interesting oddity in the behavior of squid was discovered during diving in the Red Sea by biologist Eduardo Sampaio. The male, who had already mated with the female, scared off his rivals by swinging his tentacles. Then he briefly left his mate unattended and entered a crevice where the female could lay eggs. After a short time, he returned to his partner again.
“We didn't know what he was doing. This behavior has never been seen before,”says Sampaio, Ph. D. When he talked about the strange behavior of the squid to Samantha Cheng, a biodiversity scientist at the American Museum of Natural History in New York, she said that she herself observed the same behavior in male reef squids in Indonesia. However, nothing similar in the scientific literature about squid, octopus or other cephalopods has been described previously.
In a new article published in the journal Ecology, Sampaio and Cheng detail the behavior of squid. They explain the discovered strangeness of their behavior by paternal care, which had never been noticed for squid before. Exploration of a potential nest before the female begins to lay eggs is common among monogamous species, but paternal care of any kind among cephalopods is extremely rare.
Scientists note that they do not yet fully understand this phenomenon. The discovery could change the way science thinks about squid breeding. Perhaps the relationship between males and females is much more complex than previously thought.
The strange behavior of squid turned out to be a pattern
Scientists compared Cheng's videos from Indonesia with Sampaio's videos from Egypt, and concluded that the behavior of the male squid was intentional, not accidental. They also noted that in some cases, when the female was left unattended, other males made their way to her and mated.
But why did the male abandon his partner? Even a short absence gives other males a chance to mate with her. Leaving the female unattended threatened the male's reproductive success, so the researchers decided there must be a very good reason for this.
Male squid check the nesting site before launching the female into it.
“Scientists have not seen what is really going on in the crevice. Presumably, the male could clear the area, check if another male or predator is hiding there, and that it is a safe place for the eggs,”says Sampaio.
In squid, and in cephalopods in general, females usually take care of the eggs until they hatch. Care is manifested in the provision of oxygen to the eggs. Females use their tentacles to increase the flow of water around the eggs. After hatching of eggs, in many species, the female dies altogether. Males do not take part in egg care at all.
Cephalopods are still poorly understood, as observations are carried out in aquariums
Cephalopods are still poorly researched
New research suggests scientists need to do more research on cephalopods in nature. Most of what scientists know about the behavior of this species comes from observing them in captivity, that is, in aquariums. Perhaps the artificial environment is too simple for animals, so males do not study the nesting site before launching a female into it.
“The more we learn about squid, the more we are amazed at their complexity and quirks,” says Sampaio.
Now Sampaio and Cheng are reaching out to other scientists to find out if large reef squids practice this mating behavior anywhere else in the world. As the researchers themselves say, the biggest problem in studying species that inhabit such a vast territory is obtaining comprehensive information. Earlier, I wrote that scientists use volunteers to study pikas. This allows them to get much more information. However, in the case of squid, this approach is not applicable.