The science fiction novelette by Poul Anderson The Dipteroid Phenomenon describes a plot in which
the protagonist Evalyth is one of the members of a space-faring civilisation which is rediscovering atavistic humans stranded on other planets following the fall of human civilisation from an interplanetary war in the past.
The husband of the protagonist is murdered and cannibalised by the savage guiding him through the jungle, and she finds and captures the savage's whole family in revenge, intending to execute the savage. While doing so, she discovers that all of the humans on the planet, including the civilised city-dwellers, have a tradition of cannibalising humans. The savages hunt each other for cannibalism, while the city-dwellers hunt down the savages, which they then keep as slaves for consumption.
In the end of the story, it is revealed that:
all of the male humans on the planet are unable to sexually mature normally due to a genetic mutation in their Y-chromosome, which results in them having to consume male genitals in order to reach sexual maturity.
The novel then further states that the phenomenon of having to consume males in order to mature is also found in terrestrial Diptera flies.
'Hence a dipteroid phenomenon may have appeared in man on this planet. Such a thing is unknown among higher animals elsewhere, but it is conceivable. A modification of the Y chromosome would produce it. The test for that modification, and thus the test of the hypothesis, is easily made.' The voice stopped. Evalyth heard the blood slugging in her veins. 'What are you talking about?' "The phenomenon is found among lower animals on lower worlds,' the computer told her. 'It is uncommon and so is not widely known. The name derives from the Diptera, a type of dung fly on Old Earth.'
Is this "dipteroid phenomenon" a real biological phenomenon observed in Diptera dung flies on Earth? I was unable to find a scientific paper describing this rather interesting phenomenon.
