Returning eggs to the perpendicularity.

[+Oltux72 he/him]

The life cycle of the parasite giving Aviars power has some implications. It is clear what advantages the Aviars are getting out of the symbiosis. They are not eaten because they are concealed. Going to the perpendicularity as they are hatched is a behavior that is strongly selected for.

But what is in it for the worms? At first glance a worm whose bird is eaten dies. So he won't reproduce as often. Right. But a worm whose descendants don't reach the perpendicularity cannot grant powers. In fact, we must doubt that they even survive. The worm is adapted to the perpendicularity after all. So the selection pressure ends after one generation. So how did this work?

Something returns the offspring of successful symbionts to the pool. I guess it is the chicks themselves. The coevolution could happen because birds are using the same orifice for defecation and reproduction. That way the eggs of the symbionts get attached to the eggs and to the hatchlings after hatching, who then transport them back to the perpendicularity where the cycle begins again. Hence continous selective pressure to grant powers is created.
But it would not work with mammals (except monotremata).

[Honorless he/him]

Some bird species on Earth have really complex reproductive organs and tracts due to gender wars. Female ducks in particular have dead ends in their cloacas. Perhaps the Aviar house & culture them in an organ like that. The appendix is another option, it already serves a similar function as might be needed for a hypothetical organ to house the parasitic worm. The appendix serves as a training ground for the immune system so as to prevent self-destructive auto-immune responses as well as a helpful bacteria culture.

On the other hand, birds having a cloaca (both reproductive & excretory) isn't really necessary for this kind of relationship to evolve. Birds on Earth usually ingest worm eggs while foraging in an infected area, which the Perpendicularity on Patji is. The worms probably get nourishment from the birds' gut, typical parasite stuff.

Either or both would be interesting really, since there are so many types of Aviar (and Mainlander birds, apparently)

Edited June 3, 2020 by R J
edited for clarity