Fertile hybrids

[Anthony Nolet]

Most hybrids are infertile right? But not all of them if the first statement is true. Is it possible for a hybrid to breed with one of the 2 species that bred to create the hybrid? The example I'm most interested in is a green sunfish x pumpkinseed hybrid breeding with a pure green sunfish. At night I go to the river with a flashlight and I've recently started seeing hybrids on breeding beds right next to green sunfish and pumpkinseeds but mainly Greens. I've also noticed that the hybrids this year look differently than the hybrids I've found before, not sure if they're 2 different parent makeups or if they're a hybrid that bred with pure parent fish. Older hybrid from last summer hybrid I caught this year (I think this is just a combination of different fish but not 100%)

 

[Tifftastic]

From what I have read it depends a lot on the species that are hybridizing. A common example we learn when discussing speciation and how difficult it can be to determine the lines between species of fish and amphibians is a salamander in Cali where there are four species, I can't remember the names but we'll say A, B, C and D. So A can form fertile and viable offspring with B and C suggesting that A, B and C are all the same species right? However, B can breed with C, but no offspring will be fertile. C can't breed with D at all because of different repro anatomy. However D can breed with B and create fertile hybrid offspring. Its a weird chain. Not all hybrids are created equal essentially.

I did do a quick search in the Uni database for published papers on your question and found that Pumpkinseed can produce fertile hybrid offspring with blue gill, however the sperm (while viable) cannot compete with the sperm of a conspecific. So, if a hybrid and a pumpkinseed are trying to fertilize a pumpkinseed egg at the same time the pumpkinseed sperm will "win." But if a hybrid is trying to fertilize a hybrid or a pumpkinseed egg and there are no pumpkinseed sperm around the hybrid sperm will be able to create fertile offspring with the pumpkinseed. I know these are not the specific species you asked, but they are all Lepomis genus so I would assume the same rule would apply and the hybrid offspring of the two species are fertile.

 

[MN_Rebel]

Hybrids are highly varied, that's why they looks different from other individuals. There's a good chance that some hybrids you saw were green x bluegill hybrids. Green x bluegill and Green x pumpkinseed hybrids are highly fertile but both hybrids will produce 80-90% males. That's why hybrid sunfish were highly desired for farm ponds to limited natural reproduction. Hybrids seldom nesting during breeding season. Also if the hybrids are breeding back to the purebred species, their offspring will looks like a purebred than a hybrid most times. F2 hybrids are so rare in the wild. Nature made them that way to prevent the species become hybridized too much.

 

[Anthony Nolet]

This is all good information if I go back to the river tonight I will take a picture of one of hybrids that I'm curious about.