Shouldn't rape, particularly as a tool of war, and the tendency in certain agricultural societies for second and third born sons to migrate impact this analysis? It seems both would lead to the spreading around of male Y chromosomes even in societies otherwises patrilocal.

Shouldn't rape, particularly as a tool of war, and the tendency in certain agricultural societies for second and third born sons to migrate impact this analysis?

i'd say the frequency is low. additionally, i also assume that the reproductive fitness of the offspring of raped females would be low (imagine what their prospects and supports would be in their mother's culture would be).

and the tendency in certain agricultural societies for second and third born sons to migrate impact this analysis

my understanding is that partible inheritance is more common than primogeniture.

I don't know why or how you can say rape is an uncommon tool of war or that women would not, naturally enough, protect their offspring even if they're raped. Rape is talked of extensively in the Iliad as one of the prizes of war, though in that case the women were taken back to Greece, I believe. As for the kids, the world is not made up of honor-killing Arabs, Southern slaves for instance did not mistreat their mulatto offspring to use an example from recent memory, and warm bodies were likely in shorter supply on the steppes of Eurasia a few thousand years ago, I would imagine, than they are now.

As for the second thing, I know that may be true in recent European history, but doesn't male adventuresomeness and mobility seem fairly universal, not least because men can travel more safely than women everywhere due to their physical strength. As for property division, I'm not qualified to opine.

I don't know why or how you can say rape is an uncommon tool of war or that women would not, naturally enough, protect their offspring even if they're raped. Rape is talked of extensively in the Iliad as one of the prizes of war, though in that case the women were taken back to Greece, I believe. As for the kids, the world is not made up of honor-killing Arabs, Southern slaves for instance did not mistreat their mulatto offspring to use an example from recent memory, and warm bodies were likely in shorter supply on the steppes of Eurasia a few thousand years ago, I would imagine, than they are now.

i didn't say rape was an uncommon tool of war. i said "it's frequency is low," that is, the frequency of copulations out of the total set of copulations. i'm not saying that no one is descended from rapists, we all are i'm sure at some point, but what proportion of reproductions in any given generation are rapes vs. village-to-village mate transfers? i think on average it is more the latter. southern slaves of course didn't have a normal family life, i believe they were highly matifocal as a society. as for prizes of war, well, they became concubines. i was specifically thinking of the spread of males lineages via raping local women and moving on. once you "capture" and install in your household then the situation gets a little more complex since in some societies women were in many situations chattel.

As for the second thing, I know that may be true in recent European history, but doesn't male adventuresomeness and mobility seem fairly universal, not least because men can travel more safely than women everywhere due to their physical strength. As for property division, I'm not qualified to opine.

mobility is probably more relevant when there is a frontier. e.g., 19th century USA, russia for most of its history. in other societies where the land is all occupied and the population relatively stable moving to another locale might reduce your *average* fitness since you would be lacking any familial support. in any case, primogeniture is from what i can tell the exception to the rule. it didn't hold in south asia or east asia from what i know. that's a substantial portion of humanity.

Male mobility - I remember a lecture years ago at the university, where the professor talked about some study about the distance between spouse's family homes in 19th century's Czechia. The maximum result was around 5-6 km - the distance males were willing to run there and back in one night when courting the girls from the next village.

Culture matters, too. Early horticultural societies (before conquest, and state formation) are often matrilocal. But once political states appear, societies are uniformly patrilocal, with few if any exceptions. I can document this if you like.