The first two answers in the anatomically correct succubi question suggest a parasitic approach to the concept of succubi which snatches off human organs, either the tongue or the vagina and feed off blood and human sexual excretions.

Those answers suggest that in both cases the succubi reproduces by infecting other humans through vaginal or oral sex.

Humans are already highly sexual creatures and sex has always been kind of the center of all our societies where sex is either something seen as religious or an act to empower one's nation through reproduction. For the very sexual nature of humans most cultures have their own sexual hygiene and dogmatic beliefs or behaviors.

But most importantly prostitution, not every country has brothels but prostitution is a service spread across the entire world. This to prove that sex is not just a basic need for healthy humans but affection too.

Now given the idea of succubi increasing their host sexual desires even further though hormonal manipulation then we have the perfect recipe for a giant world wide orgy.... cough

Jokes a part, it seems that with this concept humans would likely meet extinction by infection, where real humans exist no more as they get infected with the succubi parasite.

So, when every human being on the planet is infected with the succubi parasite... How does evolution keep this going?

To make things more specific I would prefer the second answer the question I linked as reference.

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    $\begingroup$ Succubus comes from Latin, and its plural is succubi. $\endgroup$
    – L.Dutch
    Apr 27, 2020 at 12:59
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    $\begingroup$ If everyone has parasite how the parasite spread? You end up with a child WWO or, restricting hormones to work only on adults, a parasite dependand on human age. So a drough might kill a lot of host. Too much sex and reproduction lead to overpopulation, which lead to people dying from hunger. So evolution goes as usuall, focus on people survivng lack of food. Everything else is secondary. $\endgroup$ Apr 27, 2020 at 13:02
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    $\begingroup$ Syphilis is highly contagious and yet humanity didn't get all infected, even when there wasn't a cure for it. What's the reason this parasite is more successful? $\endgroup$ Apr 27, 2020 at 13:25
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    $\begingroup$ @AdrianColomitchi I think the idea is that not only sex drive is higher than usuall but the additional hormones work in host advantage that no many people can refuse the sex. $\endgroup$ Apr 27, 2020 at 13:49
  • $\begingroup$ @AdrianColomitchi it alters human behavior as suggested in the linked question $\endgroup$
    – user72862
    Apr 27, 2020 at 13:49

2 Answers 2


You need to read Parasite Rex. The entire book is about parasites (especially sexual ones) and how for many species mating is a difficult cost-benefit question of whether it is worth mating versus getting infected. A lot of species struggle with figuring out if their mate is going to infect them with some disease, including humans (just look at how dealing with whether your partner has HIV/AIDS works). Most species do just fine juggling risks of infection with actual reproduction, though obviously some get infected.

Hypersexuality is a very common behavior in many infectees of sexually-transmitted parasites. If that is the case human society would rapidly shift to the point that hypersexual behavior and high appetites for sex are frowned on because they are indicators of infection and a person should not sleep with that person unless they want to get infected. No different from how we avoid animals that are obviously rabid. Moderate to low-moderate levels of sexual appetite would be considered societally optimal because that would indicate a person is not infected but wants to mate. Indeed, avoiding STDs is thought to be one reason why being frivolous with mating partners is considered a turn-off to many people.


Evolution would Favor Prudishness

The average number of partners varies greatly between different societies, so it would not spread evenly across all populations. Even in the US it ranges from an average number of 15.7 (Louisiana) partners to 2.6 (Utah) in a lifetime depending on your state. Assuming from your post that Succubus infections render the human sterile, no new humans could be born with the disease, so it would spread rapidly in societies that were sexually promiscuous, but societies that were basically monogamous would flourish, as they wouldn't have to compete for the same resources.

Many societal traditions from the ancient world curtail spread of your disease, mainly:

  • Arranged marriages, that insisted on the purity of both parties before entering.
  • Strict punishments for extramarital sex.

Sure, some people would break these norms (after all, prostitution has existed in every society), so the disease wouldn't die off. But not everyone would break the norms, and those that engaged in such behavior would effectively remove themselves from the gene pool. And if promiscuous gene-pools are cut off, there would be gradual movement towards strict monogamy worldwide.


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