One thing that continually astounds me, is just how productive some of my wild betta species can be.
Spawning seems to be a major affair with splendens. There is the initial conditioning, the often turbulent and sometimes violent courtship, and then the excruciating wait until the eggs are hatched and the fry become free-swimming.
There are often reports of males becoming depressed after being removed from their fry, and it does not seem to be all that rare that one or both partners may die either during or after spawning.
On the other hand, spawning wild bettas (at least of this complex) is a completely different affair.
I don't need to bother with separate spawning tanks, as my pairs are quite content to spawn wherever and whenever. In fact my captive-bred burdigala are so comfortable in my presence, they once started embracing while I was still pouring a bucket of water into their tank!
I've found males will recycle their previous nests if they remain intact, and spawn almost continuously in a very short period of time. They don't seem to be able to produce as many fry in one spawning as splendens can, and perhaps this is why they are able to successfully spawn with such frequency.
Male care also seems to be quite lacking once the fry become independent. From what I have read and learned from other hobbyists, splendens males that are kept in with their fry tend to be quite involved in their care even after the fry become free-swimming.
I've found my males will almost completely ignore their presence once the fry no longer return to the nest. They also seem to expend a lot less energy on defending the nest site from the neighbouring bettas as that seems to become the female's job. She will patrol the tank, only being chased away by the male if she gets too close.
Some of my females however, will build their own nests and either collect fallen eggs/fry or actively steal them. My palangkarensis female is a repeat offender and will make raids on the male's nest to see if she can't carry anything off. Like the male, she will carefully look after the eggs or young fry until they become free-swimming, and then is ready to spawn again quite soon after.
From what I have read and seen, it seems many splendens breeders will spawn only young pairs, and retire them fairly early on. I am not sure why this is the case, but I have to say that at two years of age, my Betta rutilans 'green' pair were still regularly spawning. It was only that I have since lost the female that I no longer get any fry from the remaining group.
I recall finding an article where the author also had a pair of coccina complex wild bettas that were still successfully spawning at two or three years of age. So far, it has been my experience that these smaller species do not seem to lose their willingness to 'go forth and multiply' even as the years go by.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.