
Worms with three sexes discovered in Mono Lake - respinal
https://phys.org/news/2019-09-otherworldly-worms-sexes-mono-lake.html
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dogma1138
The paper has nothing to do with their sex but rather about their resistance
to arsenic.

Nematodes often exhibit hermaphroditism, which isn’t exactly a third sex since
hermaphrodites have both male and female gonads they still have binary sexual
reproduction just with themselves and when reproducing with a male or a female
sexually they would act as a female or a male respectively during
reproduction.

As far as sexual reproduction goes this isn’t 3 sexes that require each other
to reproduce or 3 distinct sexes that can reproduce with each other
individually.

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seanhunter
Not a biologist, but there's nothing that novel about 3 sexes as such. Some
fungi have thousands of sexes[1] for example. The way I heard it explained is
from an evolutionary point of view there is selection pressure towards either
2 or very large numbers of sexes.

Very large numbers of sexes means it's very likely that when 2 individuals
meet they can sexually reproduce (whereas if you have only 2 sexes half the
time they cannot). Say there are 100 sex types of a species it might well be
that 80% of random couples could sexually reproduce together because there are
far more compatible combinations.

On the other hand, evolutionary pressure towards 2 sex types comes from
specialisation. It's very helpful for the gamete to either be large and full
of food for the developing embryo or to be small and fast to win the race to
fertilize. Once the process of specialisation starts, the largest "foodie"
gamete and smallest "fast" gamete tend to beat out all the others so you end
up with 2 sexes one of which produces eggs and the other sperm.

[1] [https://earthsky.org/earth/fungus-sexes-chromosomes-
thousand...](https://earthsky.org/earth/fungus-sexes-chromosomes-thousands)

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gus_massa
Paper: [https://www.cell.com/current-
biology/fulltext/S0960-9822(19)...](https://www.cell.com/current-
biology/fulltext/S0960-9822\(19\)31040-1)

Spoiler alert about the three sex:

> _Auanema sp. shares features, such as possessing three sexes: hermaphrodite,
> male, and female (Figures S3H–S3Q), with its closest relatives, A. rhodensis
> and A. freiburgensis [12]._

It doesn't seam to be so unusual for nematodes
[https://en.wikipedia.org/wiki/Nematode#Reproduction](https://en.wikipedia.org/wiki/Nematode#Reproduction)

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karmakaze
"and carries its young inside its body like a kangaroo"

is fascinating for works.

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soheil
How do I block submissions from phys.org?

~~~
gus_massa
I've seen a lot of linkbait from phys.org (and other press release reposter).
It's usually better to try to explain why the title (or the whole article) is
wrong than just complaining. [Someone will downvote you anyway.]

~~~
soheil
I was genuinely curious, you're right about the downvotes. A Chrome ext or a
feature like (hide) but site level on HN would be desirable. While at it why
not throw in a user level block too? I feel like a lot of people who like
phys.org may be downvoting me anyway.

