I think the name "Harlequin" was somewhere in the title, but not sure. Story is about a man who goes to another planet to learn about the sentient species there. I remember a scene where he is eating a meal with them and one pulls out a living thing called "kiritsa"(sp?) from its body and consumed it. One egg/youngster of the species becomes harlequin to act as an ambassador to the human.
This is The Eye of the Queen by Phillip Mann. The character Harlequin is a Pe-Ellian, who is considered problematic by his people, but has a deep relationship with the main human character, Marius Thorndyke, who is a kind of xeno-anthropologist specializing in first contact. The karitsa you recall, are, if I recall correctly, something like unfertilized gametes that sometimes serve as snacks (which foreshadows the novel's startling conclusion).