The MUTOs Reproductive Cycle

Due to the Godzilla skeleton found in the Phillipenes with the MUTO spores inside it, we can determine that the MUTOs during prehistoric times would have located a nearby Godzilla, killed it and then layed their eggs inside it. Now of course, from what we see in the film, the MUTOs instead use a nuclear warhead, an unatural source of radiation, as a food source for when their babies hatch, the nest being dug into the road. I can understand why they didn't kill Godzilla in the movie and use his corpse as a nest for the eggs, since they were unaware of where he was. However, what exactly do the MUTOs do during the scene where the female and male meet? I mean, I know the male gives the female the warhead as a food item for their young, but notice how she seems to hold it close to her egg sac before digging the nest? I think that by doing that, she was fertilising the eggs. That means that in prehistoric times, the MUTOs would have needed an unatural source of radiation small enough to fertilise the eggs before a Godzilla could be killed and be used as a nest. Here's what I think courtship for the MUTOs would have been like millions of years ago, and please note that this ties in to my own origins for Rodan for the sequel, which I recommend you read before this to understand what I am suggesting.

The females and males would call to each other using echolocation, and travel to each other to meet. Before encountering the female, the male would locate the nearest nearby Godzilla before flying over to a volcano where Rodans would hang around and nest. The male would gather a Rodan's egg cluster into it's mouth, with the eggs being irradiated unaturally from their parents and the volcano, before meeting the female and giving the stolen egg cluster to her so she could fertilise her eggs. Then, the pair would find the Godzillla the male had discovered before, kill it, and have the female lay her eggs inside it. She would guard the nest, with the male bringing her food and water by containing them in his jaw but not swallowing them. Then, once the babies hatched, the female would leave them to their own fate and cut her ties with the male.

What do you think? Please correct me on any errors I may have made and leave your thoughts! I apologise for this post being so long!