Human sperm cooperate on the competitive pathway to fertilization: study

Animals&#x27; shared ancestor with fungus is thought to be among <a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Choanoflagellate" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Choanoflagellate</a>, which kinda look like sperm.<p>My guess is that they were predominantly haploid (like sperm&#x2F;eggs), and just had a diploid (like most other human cells) phase for reproduction. Somewhere along the way this switched (which is thought to have happened in plants also, mosses are primarily haploid while flowering plants are primarily diploid).<p>...which is totally bonkers. It&#x27;s like if sperm&#x2F;eggs went around making all of the important decisions and only bothered to spin up a human briefly for reproductive purposes. But then the sex got a bit out of control and got a job and an apartment and now it&#x27;s the sperm who look like they&#x27;re just for reproduction.<p>Disclaimer: I took Bio 101 two semesters back, so I&#x27;m pretty much an expert.

If sperm cooperate, I wonder if the effects of the reported[1] historical decreasing sperm counts are worse than thought. For example, if the value drops by half, perhaps the decrease in fertility is not linear, but quadratic, falling to 1&#x2F;4 of the original value, because each of the 50% left has only half the average number of peers to cooperate (this is only an example. I have no idea on how fertility scales with sperm counts).<p>[1] <a href="https:&#x2F;&#x2F;www.amazon.com&#x2F;Count-Down-Threatening-Reproductive-Development-ebook&#x2F;dp&#x2F;B084G9MMVH" rel="nofollow">https:&#x2F;&#x2F;www.amazon.com&#x2F;Count-Down-Threatening-Reproductive-D...</a>

&gt; About one-fifth of mammalian (including human) sperm are typically abnormal, containing no heads, two heads, two or more tails, oddly misshapen or malfunctioning tails, and so forth.<p>TIL

Time for Robin Baker to update the seminal &quot;Sperm Wars&quot; [1]<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Sperm_Wars" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Sperm_Wars</a>

The idea that sperm cooperate is quite funny. They are sometimes used as a sort of example of how wildly competitive life is from the very start, we were in cooperation to even be born. In fact, it was a group project.

I read a book long ago called Sperm Wars. It’s almost pornographic in style but every chapter describing the biology of sperm and sex is preceded with a fictional narrative of some courting ritual.<p>Really blew my mind at the time at how complex and interconnected the behavior of sperm and egg are with general human behaviors via hormone communication.

&gt; When sperm disband their cooperativeness, it’s each pollywog for himself.<p>I&#x27;m surprised to see Nautilus implying that all sperm are male. Half of those pollywogs carry an X chromosome. You go, girls!

Some of this might not be accurate.<p>&quot;Human testes are on average 0.06 percent of body weight and sperm concentration is about 25 million per ejaculate.&quot;<p>25 million per ejaculation would fall in the &quot;low&quot; fertility category. At the other end of the range you can have 10x that amount.<p>The part about bee phallus implantation is true, but to my knowledge it does not really deter others (in honey bees at least). The queen mates with multiple males and has offspring using genetics from more than one.

That&#x27;s because sperm-cells of a single male all share the same goal. They are not really competing are they? They all have the same goal, carrying on the genes of the same individual.

&gt; When the hard-working little swimmers encounter the thicker vaginal mucus, their path is slowed. So the sperm often join together at their heads, which gives them greater swimming speed (up to 50 percent faster) than if they were to carry on individually.<p>Teamwork makes the cream work.

Well, they do all have pretty much the same dna, so it makes sense I suppose. The same way that ants cooperate.

&gt; <i>This pattern is consistent with data on the average number of male sex partners for females per birth: gorillas, one partner per birth; human beings, 1.1; baboons, 8; bonobos, 9; and common chimps, 13.</i><p>I don&#x27;t understand this statistic. &#x27;Human beings average 1.1 male sex partners per birth...&#x27; we need to see the data behind this. This isn&#x27;t implying that 1 in every 11 children are bastards, no?

&gt; In certain bee species, the male’s body literally explodes after copulation, due to a sudden increase in intra-abdominal pressure, which embeds part of the now-deceased male’s body into the female’s genital tract, preventing other males from copulating with the just-fertilized female.<p>Wrong; other males can still mate with the female. The whole point is for her to mate with multiple males. I wonder what else in this story is incorrect