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Male octopus injects female with venom during sex to avoid being eaten (newscientist.com)
93 points by delichon on March 16, 2025 | hide | past | favorite | 89 comments


Portia labiata spiders are also fun:

"Females try to kill and eat their mates during or after copulation, while males use tactics to survive copulation, but sometimes females outwit them."

https://en.wikipedia.org/wiki/Portia_labiata


also check out the book Children of Time (https://en.wikipedia.org/wiki/Children_of_Time_(novel)). Reading it now (not sure how I missed it originally), pretty good evolutionary world building based on this species :)


Children of time is such a great work of fiction. It was strange for me to root for spiders over humans


A book that has pride of place on my shelf. I found myself speed-reading through the drama surrounding the human beings so I could slowly savour the progress of the spider civilization.

A truly wonderful work of sci-fi


> The conspicuous main eyes provide vision more acute than a cat's during the day

Curious how the spider processes all this information with their tiny brain ...


SF author (and marine biologist) Peter Watts as a great little overview of Portia's "thought process" along with links to some more in-depth articles: https://rifters.com/real/2009/01/iterating-towards-bethlehem...


I'll have to check that out! I linked Children of Time in this thread which also does this well using this species


I was always wondering if brains all these spiders and flies have the capability to reconstruct the surroundings in 3D like mammals do, or their sophisticated eyes are only light and motions sensors. Observing e.g. fly evading flyswatter which resembles random walk, it's likely the latter.


Their eyes are not going to have evolved past the point of providing any incremental benefit, and a fly is after all a simple critter who's main concern is finding a pile of shit to eat, and avoid being swatted by a cow's tail. I'd guess their eyes (& visual system) are perhaps better regarded as crude visual sensor rather than anything much like the visual system of an animal that benefits from recognizing whether that shitty ass belongs to a cow vs a tiger.


In general it may be the latter. Portia spiders in particular, though, will observe a target, observe their surroundings, then navigate a complex path around and through structures that block their vision of the target to reach a destination that will allow them to attack it. Suggesting very much that they form some kind of model of their surroundings, plan a path through it, and remember that path.


Tiny brain with 8 eyes…


Why is it eight-legged creatures doing this what’s going on


how does female cannibalizing the male fit into darwin evolution theory ?

that evolution should make reproducing less efficient, either the male is dead before he finish reproducing with the female or at least, he is not able to reproduce with other females.

Yet it seems to be working just fine with other species of octopuses where the male get eaten.


With preying mantis and black widow it seemed, as their names suggest, very common for the female to eat the male after being boinked. However, it turns out that in the lab setting with a small closed environment, probably lots of lights and weird sounds, the female was freaked out, which led to her getting the first meal she could find, that being the male. In the wild, it does happen but as a last resort if food is scarce.

The orb spider figured out a hack: he ejects his member in to her after sex which keeps inseminating her from that point forward. Sure he dies, but he reproduces from beyond the grave!


Cannibalism is legitimate in the wild.

However, as you suggest it’s not necessarily a mating thing.

If the animal is hungry and there is a food source (and no reason to do anything else), the pro-survival option is chosen.


> With preying mantis and black widow it seemed, as their names suggest

The praying mantis is named after its characteristic posture while standing around.

There is no preying mantis.


Wow obvious good point. Even if it was "preying mantis", plenty of creatures prey on prey without coital cannibalism. Other spiders, insects, and even snakes do similar but lack the name to warn the male of his danger.


Isn't the orb spider really inefficient?

What if one specific mutation of orb spider is really nice but he was killed and its "member" is in a single female orb spider limiting the greatness of a good mutation I suppose which can feel counter to evolution to me I suppose.


> What if one specific mutation of orb spider is really nice but he was killed and its "member" is in a single female orb spider limiting the greatness of a good mutation

That's a very soft limit; a spider lays dozens (hundreds?) of eggs after mating once. Mortality is extremely high, so there's tons of room for "really nice" mutations to spread quickly.


It's important to say that evolution isn't versioned, and what we're observing isn't finished. We may be looking at an evolutionary dead-end. Which is to say that if eating the male is an evolutionary development, it might a poor one.

There is no logic to evolution. No decisions are being made. Evolution is reactive, and the surviving lineages may only be responding effectively to some of the external forces. Evolution doesn't happen at a species level, it happens at the individual level and has downstream effects on the species.

We're seeing evolution in action. Tragically, we (individually) won't be around long enough to observe the changes in another 100 or 200 or 1000 generations.


Eggs are way more resource-intensive than sperm. The female octopus will take care of the eggs and protect them, and then die after they hatch.

Both parents are all-in, probably because some less malleable trait or characteristic, whether environmental or hereditary, requires them to be so.


> Both parents are all-in...

THIS. The life expectancy of an octopus is extremely low - https://en.wikipedia.org/wiki/Octopus#Lifespan - and they're all-in on the "extreme number of offspring, microscopic survival rate" strategy. So for a male - it's a fairly reasonable tactic to end up as a big, nourishing meal for the female that will go all-in on producing the eggs of your decedents.


Presumably the female acquires calories with which to grow her brood.

"Unable to reproduce with other females" is probably relevant. The relative size of different genders has a lot to do with if a species is polygamous or monogamous. Larger males the former and larger females the latter.


Yes, although the fact that the male has evolved this venomous defense seems to indicate that benefit of maintaining diversity in the gene pool (maybe good genes even, if he had to compete to mate) might outweigh the benefit of being a quick snack for a post-coital hungry female.


The effect of natural selection is that the genes that propagate most are the ones that maximize the probability of that gene appearing future generations. There is no direct evolutionary pressure for an individual to behave in ways that benefit the species in general.


Yes, because there is no concept of "species" in nature, species is an arbitrary grouping we humans apply to the individuals and genetic lines that are actually involved in natural selection.

The female's genes are most likely to get passed down many generations if the males she mates with have genes that enable her male children to survive long enough to reproduce. Once a species gets into a state where females make a habit of eating the males during copulation, it can't readily evolve out of that state, because a female that is less aggressive will mate with males who can't succeed at mating with other females, leading to that line dying out. Sexual cannibalism is a local maximum.

So if at any point in the past there were evolutionary pressure that made cannibalism beneficial to the genes, we would expect to see it stick around until there's sufficient pressure against cannibalism to allow selection away from that local maximum.


> "a female that is less aggressive will mate with males who can't succeed at mating with other females"

That premise is the fundamental point that your argument hinges on and I see no reason to just assume it would be true, and can create plenty of plausible arguments (that I think are fairly self evident) for why it would be untrue.


Then please do! I'm definitely open for discussion if you care to offer any.


The goal of the male spider is to pass on his genes as much as possible. Mates who don't kill him are rather more preferable than ones that do!


But that is true regardless of whether a male is fit enough to survive a cannibalistic female, which means that pacifist females do not have an advantage in natural selection:

As long as there are enough males in circulation that can succeed in fertilizing before being eaten, then there's no pressure on females to drop the cannibalistic strategy. Any male that cannot win the cannibalism game can only fertilize pacifist females, but a male that can win the cannibalism game has genes that can be passed on to both cannibalistic and pacifist females. So the genes of cannibalistic females have broader reach within a species that has already gotten to majority-cannibalistic because her male offspring can fertilize both types of female rather than just one type.

Again, to GP's point, just because non-cannibalism would be more beneficial to the species as a whole doesn't mean that evolutionary pressure on individual genetic lines will select away from it. The individual line is often better off being selfish and selecting the strategy that gives them the broadest possible range of propagation (hence Richard Dawkins' title, The Selfish Gene), which in this case is cannibalism.


They wouldn't have any way of knowing this before choosing the female.

I suppose the can develop a more advanced social structure with prenups, courts, and police, but then we're talking about millions of years.


> there is no concept of "species" in nature, species is an arbitrary grouping we humans apply

The results of a cluster analysis are not arbitrary, even if the exact location of the boundaries can be a bit fuzzy.


What local maxima might humans be stuck in?


Emotional and social drives that keep us from letting genetic defects to die out of the gene pool.


Have you considered the technology developed to save/help due to that drive could be and probably is, a net benefit to science?

And I am fairly certain that evolution requires much longer time scales than the 10k years of civilization humans have existed in?


> either the male is dead before he finish reproducing with the female or at least, he is not able to reproduce with other females

In addition to the sibling comment's caveats, it's worth mentioning that the latter might actually be an advantage? If the male is able to continue reproducing with an unbounded number of females, and the females are limited by how often they can lay eggs (or how quickly they can after copulation), a mutation that causes females to prevent males from reproducing with other females could potentially drown out the ability of females without those mutations to reproduce (e.g. if those females were able to copulate with most males first, they'd be the only ones to produce offspring, and there could even be other adaptions or mutations that aid them in the "first to copulate" race).


Maybe the female can use the proteins for her offspring, and there are more offspring to offset the lost male.


Game theory.

The female benefits from a meal.

The male benefits via procreation.

A different choice by either party would be suboptimal.


Go read The selfish gene, these things are being discussed in depth in the chapter “The war between sexes”.


Note to self: Be sure to die with a sufficiently well-buffed Karma to avoid rebirth as a member of Hapalochlaena fasciata.


Funniest joke ever in YN



In human terms, is this male octopus behavior comparable to drugging someone and then raping her?


You are thinking Sharks. They may even eat the female by accident.

For this octopus, it is more like making a prenuptial agreement, or gifting assets to family, or a public limited company.


No. There's no concept of rape among animals.


This sounds incredibly illegal.


We need to extend the legal system to the animal kingdom! There are millions of bacteria getting away with things.


I wonder how human society would evolve if this were the case for us.


We'd go extinct. Spiders can have hundreds of offspring per 'birth.' Humans have, on average, about one. You need each woman to have at least 2 children for populations to stay the same. Which, in this case would mean you'd need at least 2 men.

An evolution (or artificial 'population management') where males are 66% likely or otherwise born at a 2:1 ratio wouldn't work because then you need each woman to have 3 children to create a sustainable population, meaning you need an even higher ratio of males - and so on recursively towards infinite male:female ratios.


I mean, it all depends on what you want to assume. You can assume that a woman in this case will have more offspring, and continue reasoning from there.


You mean if a woman could destroy a man for (not) having sex? Men would avoid sex, cohabitation, marriage and families. For society it would mean less babies, demographic and economical decline.


Yep, exactly what is happening in rich countries at the moment. The human female behavior is much closer to other species than we like to pretend. Because we got too arrogant with our "smartness".


In Russia, China, Japan and many other countries, women are choosing sex with birth control as well as zero sex = forced demographic decline. China just purchased 300,000 fertile young women from North Korea - I wonder if they are allowed birth control or if this is a domestic forced breeding experiment?


No need to wonder, you can already observe the results going on at the moment.

Women don't do outright cannibalism since humans are more sophisticated, but women absolutely kill (figuratively) their mate/husband to extract as much ressource as possible (regardless of them having offspring in needs or not).

They are biologically programmed for that, but we forgot about it and/or we like to pretend this is not happening.

Reality doesn't care much about feeling, and with little countermeasures afforded to the men, birthrate has been going down tremendously in every country where women power has been unmatched.

So, the answer is actually pretty simple: it will die down until the only ones left are the males that found a new "venom" and are willing to use it.


From personal observation I don't think it's worries about the wife getting the house that are stopping people having kids. I think there's more of an issue with the current system encouraging everyone to get high paying jobs and the cost of housing, education and so on getting bit up by those making life hard for anyone who doesn't play along with that system, and hard for anyone who has kids.


So, fertility rates are dropping because men are scared of women extracting resources from them?

Too much Andrew Tate?


I'm not the person you were replying to, but for many men it is more of the divorce issue rather than extracting resources during marriage.

There are horror stories where a wife divorces the man and gets the house, custody of the kids, child support, alimony, etc. Many men just opt to not get married for fear that might happen to them.


Don't motte-and-bailey for them.

They didn't just claim that divorces can have unfavorable results for men which is a trivial claim.

They claimed birth rates are tumbling because women have attained the extractive power mentioned in their post and that, if left unchecked, human society will continue dying down... until all that's left is the sort of man that he likens to the venomous male octopus.


It is the same issue though.

Many people don't want to have kids unless they are married. They don't get married because of the issues I mentioned.

Even if you ignore that, you may have to pay child support if the woman you slept with leaves you.


Is a pre-nup not solving exactly this problem? Or is maybe a pre-nup not a thing for various reasons - not known, not acceptable, not possible under local law...


It depends. If you buy the home together after marriage, even if it was entirely the man's money, it can lead to the man losing the house. I don't think a prenup can exempt a man from child support or guarantee custody of the children.

Also, asking for a prenup is not exactly the easiest thing. Can you imagine saying, hey I want to get married, quite possibly saying "till death do us part", but can you agree too this prenup for when we fail. Starting a marriage with the idea that you will fail doesn't seem great to me.

I read that some politicians in a. state (don't remember which), were talking about allowing a couple to remove the right of a no fault divorce, only allow at fault divorces. I think if such a thing becomes a law, that would help boost a lot of confidence for men.


I only know about Andrew Tate because of 2 things: general chatter about him and a small (about 10 min) YouTube critic of him that I randomly watched a few days ago.

He is obviously a despicable character but it's not surprising that he was able to get where he is. He is the symptom of a general sickness nobody wants to acknowledge, the only ones breaking through are the extreme assholes, nobody listen to the nuanced position and we even tell them they are like those extreme assholes.

Which is exactly what you did, and you very astutely showed exactly that there is a problem and that you are part of the problem.

Good job, thanks.


Look up what happened to TechLead.


It's not worth wondering. A core tenant of evolution is that it's a random mutation, and that some random mutation is favorable. It's very Life of Pi, you have to make your own truth out of this because it won't make sense.


If? never been married, right? PS. You may think of your credit card as your "venom", so you won't get eat alive in a divorce process lol


saw an episode of dateline like this - but humans :)


Disappointed that the author of the article has a German name but didn’t coin a long single German word for this.


I guess becoming venonmous is evolutionarily easier than becoming better lovers.


The female protects the eggs on her own and then invariably dies, so there's not a lot of reason to invest in a relationship.


Talk about "toxic masculinity"…


More like a solid prenup, hey?


Well, when you're going up against "cannibalistic femininity", it seems less toxic...


Venomous masculinity


Venomous Femininity is a good tongue twister and a solid trivia team name


As opposed to "lethal femininity", which is what the male octopus gets if he doesn't disable the female?


The alien in the TV series the resident alien is descended from octopii.


The plural of octopus is octopuses.

But if you want to sound more latin, octopus is a third declension noun, and those have nominative plurals that tend to end in -es, rather than the second declension which ends in -us for singular or -i for plural. Third declension nouns whose nominative form ends in -s also tend to change their root's final consonant when you change the suffix. (Eg. opus -> opera. That one doesn't end in -es because it's neuter.)

All this to say, the latin plural of octopus is octopodes.


Yeah sure but we don't speak latin, English is a hodgepodge of a dozen other languages, both dead and alive, and the only value that determines whether something is correct in english or not is common usage. And octopi is used often enough to not really be incorrect. You might as well be complaining that "ain't" isn't a word despite it clearly being so ever since Dickens used it.


This is a specific case of trying to imitate the rules of Latin, incorrectly.

Another one that we misunderstand a lot is virus. It looks like the typical second declension thing ending in -us. It is actually a rare categorization of word, the 4th declension.

But it is a common occurrence in languages that when rules are complicated and confusing that they get generalized to simpler patterns from elsewhere in the language.

Romance languages have done that to Latin too! I gave an example of opera being the plural of opus. A lot of romance languages have reinterpreted neuter plurals as feminine singulars, because of that -a suffix.


> And octopi is used often enough to not really be incorrect.

By that logic irregardless is also not really incorrect.


What does ain't mean?


Isn't. Ain't is UK.


Ain't is also common in the US, but is stigmatized.

In the US, it is regional to the east coast, both north and south. It is also common in African American speech.


VS, octapie, which is what the females are dreaming of, instead of getting envenomated

lively bunch, reclusive, come in all sizes, from extra tiny, to back off quick, and a whole other complex octapoid lifestyle

I regularly interact with spiders, wolf spiders bieng my favorites by far, sometimes called jumping spiders, they are sight hunters and dont build webs, and seem to stay in a certain teritory for days or weeks, before moving on


Why would he try to sound more latin when the word octopus does come from ancient greek? I think that's the cause for this common error. People assuming a word is latin just because it ends in '-us'.


I thought everybody did this.


If you mean that forced sex/rape is prevalent in nature, then yes, there are many species that use this method/approach. If you want to make humor about rape, I'll refer you to what Ricky Gervais said on the matter (look it up).


I can't find what Ricky Gervais said on the subject (which I imagine was recent), only news articles about an Edinburgh show he did in 2009. (We're off-topic, but) I'd appreciate a link or quotation.


It's just how they make sex more interesting. Most only live a year or two, and you only live once.




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