So if the climate is moving out of the optimal temperature for the species, it might make sense for you to produce more females, because they are a lower risk strategy?
This seems confused to me. In general, males are more risk-seeking than females because (inclusive) fitness is not a linear function of successfulness at endeavors, with the function being closer to linear for males and more like linear-with-a-cutoff for females. But males and females are still both perfectly risk-neutral when measured in the unit of fitness, since that follows from the definition of expected fitness which is what needs to be greater than average in order for a mutation to propagate throughout a population.
I would expect that if a species has more females than males in some circumstances, then either it is because females are cheaper to raise for some reason, or else that it is due to a fact of biology that the DNA can’t really control directly.
Yes! For the individual, it does not make sense to adjust the sex ratio with changes in climate, but for the species overall it’s not that bad or even positive. Sex chromosomes do a much better job for the individual here (And would be selected for if temperature changes were happening too often). I do think I had confused thinking at the time, because I also had just read about a theory in humans that high status females supposedly produce more males (so payoff could be different between low and high status, but that doesn’t apply in this case, and it’s not born out well empirically anyway).
What I do think is true: It might not be that much of a coincidence that climate change would lead to more females. If it was the other way around, there is a higher likelihood the species would have gone extinct from a meteor, and we wouldn’t observe it today. Having 1% females and 99% males is going to lead to a really bad population bottleneck, but having 1% males and 99% females just means the remaining males have little competition (the effective population is still reduced to some extent). The fact that turtles don’t fit this pattern and look like they should have gone extinct with the last meteor tells you how weak and slow selection between species is.
I was thinking of this when I saw these articles complaining how sex ratios are supposedly endangering sea turtles. It doesn’t seem obvious to me that the sex ratios alone should be a problem (although 1⁄99 is probably bad).
This seems confused to me. In general, males are more risk-seeking than females because (inclusive) fitness is not a linear function of successfulness at endeavors, with the function being closer to linear for males and more like linear-with-a-cutoff for females. But males and females are still both perfectly risk-neutral when measured in the unit of fitness, since that follows from the definition of expected fitness which is what needs to be greater than average in order for a mutation to propagate throughout a population.
I would expect that if a species has more females than males in some circumstances, then either it is because females are cheaper to raise for some reason, or else that it is due to a fact of biology that the DNA can’t really control directly.
Yes! For the individual, it does not make sense to adjust the sex ratio with changes in climate, but for the species overall it’s not that bad or even positive. Sex chromosomes do a much better job for the individual here (And would be selected for if temperature changes were happening too often). I do think I had confused thinking at the time, because I also had just read about a theory in humans that high status females supposedly produce more males (so payoff could be different between low and high status, but that doesn’t apply in this case, and it’s not born out well empirically anyway).
What I do think is true: It might not be that much of a coincidence that climate change would lead to more females. If it was the other way around, there is a higher likelihood the species would have gone extinct from a meteor, and we wouldn’t observe it today. Having 1% females and 99% males is going to lead to a really bad population bottleneck, but having 1% males and 99% females just means the remaining males have little competition (the effective population is still reduced to some extent). The fact that turtles don’t fit this pattern and look like they should have gone extinct with the last meteor tells you how weak and slow selection between species is.
I was thinking of this when I saw these articles complaining how sex ratios are supposedly endangering sea turtles. It doesn’t seem obvious to me that the sex ratios alone should be a problem (although 1⁄99 is probably bad).