Sex determination based on food availability

[mark!]

[Mentor Note -- Merged accidental double-thread-start]

In which animals is sex determination based on either food availability.

Females of the Common reed frog have shown to exhibit a sex change, which is thought to occur due to low male density in the environment, so that's not quite what I mean.

other animals, when resources are scarce, mothers give birth to fewer males than normal.

Then there's the Desert Greenland Whiptail lizard, who displays parthenogenesis, but when does it do that? How does the environment affect internal biology, such as the presence of predators?

 

[mark!]

In which animals is sex determination based on food availability?
And as a side question: In which animals is sex determination based on the presence of predators?

Let me elaborate on both questions.
Females of the common reed frog have shown to exhibit a sex change, which is thought to occur due to low male density in the environment, so that's not quite what I mean.
Then there's the Desert Greenland Whiptail lizard, who displays parthenogenesis. But why/how/when does it do that? How does the environment affect internal biology, such as the presence of predators? Does such presence affect anything to any animal?

In this movie, it says that: "In certain animals, when resources are scarce, mothers give birth to fewer males than normal. Somehow, female biology suppresses boy survival in the womb during tough times, and boost it when times are good.".
Why would that be so? What does food availability have to do with sex determination?

So yes, I'm asking 2 question, but taken together, I'm actually after 1 question: what does sex determination have to do with any threat external to the womb?

 

[pinball1970]

In which animals is sex determination based on food availability?
And as a side question: In which animals is sex determination based on the presence of predators?

Let me elaborate on both questions.
Females of the common reed frog have shown to exhibit a sex change, which is thought to occur due to low male density in the environment, so that's not quite what I mean.
Then there's the Desert Greenland Whiptail lizard, who displays parthenogenesis. But why/how/when does it do that? How does the environment affect internal biology, such as the presence of predators? Does such presence affect anything to any animal?

In this movie, it says that: "In certain animals, when resources are scarce, mothers give birth to fewer males than normal. Somehow, female biology suppresses boy survival in the womb during tough times, and boost it when times are good.".
Why would that be so? What does food availability have to do with sex determination?

So yes, I'm asking 2 question, but taken together, I'm actually after 1 question: what does sex determination have to do with any threat external to the womb?

This is interesting. Trivers work features in Dawkins books.

Diet.

https://academic.oup.com/biolreprod/article/71/4/1063/2666975

I would look at Turtles too not diet, egg Temperature determines sex.

These creatures are fascinating, I don't think you can mention sex and organisms without mentioning these.
One Jim has mentioned.

https://en.m.wikipedia.org/wiki/Rotifer

 

[mark!]

Diet.

Sex determination NOT due to external/environmental factors, then?

 

[pinball1970]

Sex determination NOT due to external/environmental factors, then?

If it is not external then it is genetic