Covered in the popular media with the engaging headline Scientists discover how to make squid go completely berserk is a recent study about squid pheromones.
Squid species of a particular family, Loliginidae, are famous for their spawning aggregations. They gather together in certain areas at certain times of the year, and the females lay eggs in elongate capsules attached to the seafloor. A cluster of capsules is often referred to as an "egg mop" and a collection of mops as an "egg bed." Stumbling upon on egg bed while diving can be a dramatic sight.
Apparently, for at least one loliginid species, Loligo pealeii, a specific chemical on the outside of the egg capsules causes aggressive behavior in male squid.
Coming in contact with this molecule will typically cause males to battle with other males, apparently in an attempt to get at females, even when females are not around. . . . Aggression is generally thought to be a rather complex process, involving some combination of neural, hormonal, physiological and psychological stimuli. "Instead, we have an animal that, if it just touches this molecule, bam, the aggression happens instantly," researcher Roger Hanlon, a behavioral ecologist at the Marine Biological Laboratory at Woods Hole in Massachusetts, told LiveScience. "A link between a molecule and a behavior that is that direct is not the commonest thing in science."
In other words, behavioral scientists wish their work were always this straightforward!
What is particularly cool about this molecule is its relation to a family of molecules that have been described from mammals:
These "beta-microseminoproteins" are generally found in reproductive glands and are seen at high levels in human and mouse semen.
So the squid egg chemical, produced by females, is closely related to a mammal semen chemical, produced by males. How curious!
Here's the paper. And the whole thing is summed up nicely in a Graphical Abstract:
