No. Well, kinda... Oof, that's a complicated issue. There's actually one single known species which is functionally all-male. 98% of all individuals of the species Hypseleotris are, in fact, male and their species is healthy despite the female genotype being on it's way to extinction. So far, that is the only known species that works that way. What they're doing is called "sexual parasitism". The individuals of the species reproduce through sexual intercourse with a closely related species, just like you would expect from any sexually reproducing species. The resulting zygote however, only carries the chromosomes of the parasitic parent species, making the offspring functionally clones of the parasitic parent. Practically all sexually parasitic species are female, which is owed to the fact, that only the egg has the ability and facilities to actually develop into a multicellular individual, an ability that the sperm lacks entirely, so the likelyhood of this ability developing is heavily tilted to the female specimens of a given species. Nonetheless, there's the possibility of an all-male species reproducing sexually. But, if you paid attention, sexual parasites still need a host counterpart, even the all-female ones.hammerofglass wrote: ↑Wed Jun 05, 2024 6:02 amSingle sex would be. All the ones we know of are all female, anyway.
Now let's talk about bees. Did you know, that you could argue that bees are actually a male species, despite practically all bees you're gonna meet in your daily life being females? See, bees and some other insects are kinda funny. They can reproduce without the involvement of sperm, but the result of the gestation of such an unfertilized haploid egg is always a male individual. Only fertilized, diploid eggs develop into females (both for queens and workers). And this is really wierd, since the vast majority of sexually dimorphic species that can reproduce through parthenogenisis produce female offspring when they do that, for obvious reasons.
Nature's kinda wild and defies easy answers and that's even before we consider species that reproduce sexually, but need more than two individuals to reproduce or species that reproduce sexually but through hermaphrodism and self-insemination or hermaphrodism without self-insemination. Or, even wilder, species that have both exclusively male and female specimens, which are specifically not hermaphrodites, but whose individuals can relatively freely switch between which sex they are even in their adult stages.
And as for species that reproduce asexually, well, the definition of male and female hinges on sexual reproduction, so calling a species that reproduces through, for example, parthenogenisis exclusively, defies such categorization outright.
