Agreed with m8e. I started this one because it is distinct from the black widow trope in that in a lot of these fictional situations, there does not seem to be extreme malice on the part of the female.
Sometimes, as in the case of the H'nemthe, both genders regarded it (in a possibly misguided way) as being just part of life's cycle and regarded it as being true love if the normal process was followed. Male H'nemthe willingly participated, as they believed that if they died this way, they would be spiritual guardians for their offspring in the next world.
Compare this with the black widow trope, where the killing tends to be carried out for malicious motives. Also, in the world of fiction, the black widow trope is not necessarily to be entwined with sex and reproduction (though it is with black widow spiders in real life). In the context of the trope I have created, it is not necessarily entwined with malice (i.e. hatred) and also, this trope deals specifically with when the killing happens following sex and conception.
Apologies for my failure to follow due process in the creation of this trope: - I am new to this Wiki and I am still struggling to understand how things work.