Why do women engage in slut-shaming of attractive women who display their bodies and their sexuality? Women have evolved a tendency to compete for the ‘best’ mates because acquiring a partner with good genes who was able to invest in offspring would have increased their reproductive success in the ancestral environment. Whilst men would have often competed for mates directly, for example, using physical aggression, this was more risky for women. A woman who sustained physical injury risked her fertility and compromised the survival chances of her offspring, who would have been very dependent on her. This meant that there was a selection pressure on women to avoid direct aggression where possible and, consistent with this, we found that women show much greater fear of physical harm and have better inhibitory control. They are therefore able, for example, to inhibit their anger to a greater extent than men and thereby avoid physical aggression.
This meant that women needed an alternative means of competing for mates in the ancestral environment. Women primarily compete by epigamic display – the presentation of attractiveness and mate quality to the opposite sex. Ultimately this is why women often invest so much in their appearance, and it is the ultimate motivation behind many selfies, naked or otherwise. Not only does this form of mate competition reduce the risk of injury compared to aggressive, physical competition, it is better suited to the mate competition needs of women because male mate preferences are heavily focused on female physical attractiveness for the reasons described above – it indicates health, fertility and good genes.
However, epigamic display also serves to deter rivals by the demonstration of mate quality. And this is why the most attractive women are more likely to be subject to slut-shaming as a means of trying to damage their perceived mate quality, reduce their success in mate competition and increase the success of their rivals. Slut-shaming is a form of indirect (non-face-to-face) aggression. Indirect aggression may be used as a mate competition tactic when epigamic display is unlikely to be successful or competition for mates is high. It also avoids some of the risks associated with direct, physical aggression, and it is often extremely effective in damaging physically attractive rivals. It relies on another key aspect of male mate preferences – preference for indicators of faithfulness. Whilst indicators of promiscuity are likely to be attractive to men seeking short-term partners since they may indicate availability, the opposite is true for men seeking long-term partners. Men value indicators of fidelity in long-term partners due to the need to avoid cuckoldry (unknowingly raising another man’s child as a consequence of female infidelity) when investing in offspring.
This means that when women compete for long-term partners, casting aspersions on the sexual reputation of rivals is a powerful weapon. If a woman is physically attractive, she may display her mate quality and is likely to be successful in attracting a high quality partner. However, other women can damage the perceived mate quality of an attractive rival by claiming that her display of attractiveness indicates promiscuity. Condemning this display can also serve to enhance a woman’s own mate quality by establishing her as (apparently) less likely to be promiscuous.

Replies are a crash course in intrasexual competition btw
We have looked at some of the things that a female might do if she has been deserted by her mate. But these all have the air of making the best of a bad job. Is there anything a female can do to reduce the extent to which her mate exploits her in the first place? She has a strong card in her hand. She can refuse to copulate. She is in demand, in a seller's market. This is because she brings the dowry of a large, nutritious egg. A male who successfully copulates gains a valuable food reserve for his offspring. The female is potentially in a position to drive a hard bargain before she copulates. Once she has copulated she has played her ace - her egg has been committed to the male. It is all very well to talk about driving hard bargains, but we know very well it is not really like that. Is there any realistic way in which something equivalent to driving a hard bargain could evolve by natural selection? I shall consider two main possibilities, called the domestic-bliss strategy, and the he-man strategy.
The simplest version of the domestic-bliss strategy is this. The female looks the male over, and tries to spot signs of fidelity and domesticity in advance. There is bound to be variation in the population of males in their predisposition to be faithful husbands. If females could recognize such qualities in advance, they could benefit themselves by choosing males possessing them. One way for a female to do this is to play hard to get for a long time, to be coy. Any male who is not patient enough to wait until the female eventually consents to copulate is not likely to be a good bet as a faithful husband. By insisting on a long engagement period, a female weeds out casual suitors, and only finally copulates with a male who has proved his qualities of fidelity and perseverance in advance. Feminine coyness is in fact very common among animals, and so are prolonged courtship or engagement periods. As we have already seen, a long engagement can also benefit a male where there is a danger of his being duped into caring for another male's child. In order for a father to support his child, he must be able to recognize it as his own. Michael Price and colleagues have found modern evidence that moral opposition against promiscuity evolves in environments where paternal care is crucial for families. https://evolution-institute.org/the-real-reason-people-think-promiscuity-is-wrong/
https://x.com/SteveStuWill/status/1895236873527926807

Considering males' preference for females as long-term partners with no, or limited, sexual experience [9], it seems curious that females would be biased against ‘promiscuous’ rivals. On balance, should females not be pleased that their competitors are engaging in behaviour that debases their mate value? According to Baumeister & Twenge [73], females are threatened by promiscuous females because ‘sex is a limited resource that women use to negotiate with men, and scarcity gives women an advantage’ (p. 166). That is, females, not males, suppress the sexuality of other females and they do so by using ‘informal sanctions such as ostracism and derogatory gossip’ (p. 172). In other words, females punish other females who seem to make sex too readily available using indirect aggression [74–77]. There are some studies supporting this line of reasoning. For example, in a study of adolescents, Leenaars et al. [44] found that for girls and not boys, recent sexual behaviour was associated with increased indirect peer victimization—a finding that was, above all, present for older adolescent girls. In another study, Vaillancourt & Sharma [78] found very strong support for women's intolerance of sexy peers. In their experiment, young women were randomly assigned in dyads to one of two conditions. In the first condition, the dyad's conversation was interrupted by an attractive female confederate who was dressed in sexy clothing; whereas in the second condition, participants were interrupted by the same confederate who was dressed in a conservative manner (figure 1). Participants were secretly video-recorded (with audio) and their reactions to the presence of the confederate were coded by independent female raters blind to condition. Results of this experiment were striking—with the exception of two women, all of the participants who were coded as engaging in indirect aggression were assigned to the sexy condition.
"She Had A Pretty Little Body, But She Always Wore Baggy Clothes!" - Fruity Like A Smoov-E!
As I showed in a paper, there is a mistake in Triver's reasoning here. He thought that prior investment in itself committed an individual to future investment. This is fallacious economics. A business man should never say 'I have already invested so much in the Concorde airliner (for instance) that I cannot afford to scrap it now.' He should always ask instead whether it would pay him in the future, to cut his losses, and abandon the project now, even though he has already invested heavily in it. Similarly, it is no use a female forcing a male to invest heavily in her in the hope that this, on its own, will deter the male from subsequently deserting. This version of the domestic-bliss strategy depends upon one further crucial assumption. This is that a majority of the females can be relied upon to play the same game. If there are loose females in the population, prepared to welcome males who have deserted their wives, then it could pay a male to desert his wife, no matter how much he has already invested in her children.
https://twitter.com/DegenRolf/status/1076395604769718272

"She'll Have A Pickett Sign In Her Hand From Sun Up To Sun Down!" - Mac Minister Much therefore depends on how the majority of females behave. If we were allowed to think in terms of a conspiracy of females there would be no problem. But a conspiracy of females can no more evolve than the conspiracy of doves which we considered in Chapter 5. Instead, we must look for evolutionary stable strategies. Let us take Maynard Smith's method of analysing aggressive contests, and apply it to sex. It will be a little bit more complicated than the case of the hawks and doves, because we shall have two female strategies and two male strategies.
As in Maynard Smith's studies, the word 'strategy' refers to a blind unconscious behavior program. Our two female strategies will be called coy and fast, and the two male strategies will be called faithful and philanderer. The behavioural rules of the four types are as follows. Coy females will not copulate with a male until he has gone through a long and expensive courtship period lasting several weeks. Fast females will copulate immediately with anybody. Faithful males are prepared to go on courting for a long time, and after copulation they stay with the female and help her to rear the young. Philanderer males lose patience quickly if a female will not copulate with them straight away: they go off and look for another female; after copulation too they do not stay and act as good fathers, but go off in search of fresh females. As in the case of the hawks and doves, these are not the only possible strategies, but it is illuminating to study their fates nevertheless.
Like Maynard Smith, we shall use some arbitrary hypothetical values for the various costs and benefits. To be more general it can be done with algebraic symbols, but numbers are easier to understand. Suppose that the genetic pay-off gained by each parent when a child is reared successfully is +15 units. The cost of rearing one child, the cost of all its food, all the time spent looking after it, and all the risks taken on its behalf, is -20 units. The cost is expressed as negative, because it is 'paid out' by the parents. Also negative is the cost of wasting time in prolonged courtship. Let this cost be -3 units.
Imagine if we have a population in which all the females are coy, and all the males are faithful. It is an ideal monogamous society. In each couple, the male and female both get the same average pay-off. They get +15 for each child reared; they share the cost of rearing it (-20) equally between the two of them, and average of -10 each. They both pay the -3 point penalty for wasting time in prolonged courtship. The average pay-off for each is therefore +10-10-3 = +2.
Now suppose a single fast female enters the population. She does very well. She does not pay the cost of delay, because she does not indulge in prolonged courtship. Since all the males in the population are faithful, she can reckon on finding a good father for her children whoever she mates with. Her average pay-off per child is +15-10 = +5. She is 3 units better off than her coy rivals. Therefore fast genes will start to spread.
If the success of fast females is so great that they come to predominate in the population, things will start to change in the male camp too. So far, faithful males have had a monopoly. But now if a philanderer male arises in the population, he starts to do better than his faithful rivals. In a population where all the females are fast, the pickings for a philanderer male are rich indeed. He gets the +15 points if a child is successfully reared, and he pays neither of the two costs. What this lack of cost mainly means to him is that he is free to go off and mate with new females. Each of his unfortunate wives struggles on alone with the child, paying the entire -20 point cost, although she does not pay anything for wasting time in courting. The net pay-off for a fast female when she encounters a philanderer male is +15-20 = -5; the pay-off to the philanderer himself is +15. In a population in which all the females are fast, philanderer genes will spread like wildfire.
To complete the hypothetical cycle, when coy females increase in numbers so much that they predominate, the philanderer males, who had such an easy time with the fast females, start to feel the pinch. Female after female insists on a long and arduous courtship. The philanderers flit from female to female, and always the story is the same. The net pay-off for a philanderer male when all the females are coy is zero. Now if a single faithful male should turn up, he is the only one with whom the coy females will mate. His net pay-off is +2, better than that of the philanderers. So, faithful genes start to increase, and we come full circle.
As in the case of the aggression analysis, I have told the story as though it was an endless oscillation. But, as in that case, it can be shown that really there would be no oscillation. The system would converge to a stable state. If you do the sums, it turns out that a population in which 5/6 of the females are coy, and 5/8 of the males faithful, is evolutionarily stable. This is, of course, just for the particular arbitrary numbers that we started out with, but it is easy to work out what the stable ratios would be for any other arbitrary assumptions.
As in Maynard Smith's analyses, we do not have to think of there being two different sorts of male and two different sorts of female.The ESS could equally well be achieved if each male spends 5/8 of his time being faithful and the rest of his time philandering; and each female spends 5/6 of her time being coy and 1/6 of her time being fast. Whichever way we think of the ESS, what it means is this. Any tendency for members of either sex to deviate from their appropriate stable ratio will be penalized by a consequent change in the ratio of strategies of the other sex, which is, in turn, to the disadvantage of the original deviant. Therefore the ESS will be preserved.
We can conclude that it is certainly possible for a population consisting largely of coy females and faithful males to evolve. In these circumstances the domestic-bliss strategy for females really does seem to work. We do not have to think in terms of a conspiracy of coy females. Coyness can actually pay a female's selfish genes.
Also useful to the female is the practice I have already mentioned of courtship feeding by the male. In birds this has usually been regarded as a kind of regression to juvenile behaviour on the part of the female. She begs from the male, using the same gestures as a young bird would use. It has been supposed that this is automatically attractive to the male, in the same way as a man finds a lisp or pouting lips attractive in an adult woman. The female bird at this time needs all the extra food she can get, for she is building up her reserves for the effort of manufacturing her enormous eggs. Courtship feeding by the male probably represents direct investment by him in the eggs themselves. It therefore has the effect of reducing the disparity between the two parents in their initial investment in the young.
Several insects and spiders also demonstrate the phenomenon of courtship feeding. Here an alternative interpretation has sometimes been only too obvious. Since, as in the case of the praying mantis, the male may be in danger of being eaten by the larger female, anything that he can do to reduce her appetite maybe to his advantage. There is a macabre sense in which the unfortunate male mantis can be said to invest in his children. He is used as food to help make the eggs which will then be fertilized, posthumously, by his own stored sperms.
A female, playing the domestic-bliss strategy, who simply looks the males over and tries to recognize qualities of fidelity in advance, lays herself open to deception. Any male who can pass himself off as a good loyal domestic type, but who in reality is concealing a strong tendency towards desertion and unfaithfulness, could have a great advantage. As long as his deserted former wives have any chance of bringing up some of the children, the philanderer stands to pass on more genes than a rival male who is an honest husband and father. Genes for effective deception by males will tend to be favoured in the gene pool.
Conversely, natural selection will tend to favour females who become good at seeing through such deception. One way they can do this is to play especially hard to get when they are courted by a new male, but in successive breeding seasons to be increasingly ready to accept quickly the advances of last year's mate. This will automatically penalize young males embarking on their first breeding season, whether they are deceivers or not. The brood of naive first year females would tend to contain a relatively high proportion of genes from unfaithful fathers, but faithful fathers have the advantage in the second and subsequent years of a mother's life, for they do not have to go through the same prolonged energy-wasting and time-consuming courtship rituals. If the majority of individuals in a population are the children of experienced rather than naive mothers—a reasonable assumption in any long-lived species—genes for honest, good fatherhood will come to prevail in the gene pool.

https://twitter.com/RealYeyoZa/status/1177862754880950272
Agree, just that intrasexual competition explains a lot (not everything, but a lot) about nastiness and insults in both sexes

https://www.semanticscholar.org/paper/Intolerance-of-sexy-peers%3A-intrasexual-competition-Vaillancourt-Sharma/1f9d8938184328a4021dd37d1a7ceb0e37392495
https://www.sciencedirect.com/science/article/pii/S1090513805000577
https://www.medicaldaily.com/psychology-bitchiness-women-use-slut-shaming-defense-tactic-263531
The Short Skirt Police: Feminist Fundamentalism At PAX http://www.advicegoddess.com/archives/2017/03/13/the_short_skirt.html#.WMaYdDl9ruI.twitter …

#PAX via @Yeyoza
https://www.psypost.org/2018/12/women-but-not-men-seek-to-actively-punish-sexualized-women-study-finds-5283
https://www.youtube.com/watch?v=55M_9U6_lE4