To avoid predators, the lizards need a back pattern that matches their behavior. Sneaky yellow-throated males like to hide in the grass and need a barred pattern that breaks up the outline of their body so it blends in with the background. Aggressive orange males spend a lot of time in the open and need stripes to help them escape from predators (the optical effect of stripes on fast-moving prey makes them hard to catch).
But the genes that control behavior and back pattern are not linked, so a lizard could end up with a mismatch that would leave it highly vulnerable to predators--wearing stripes and trying to hide in the grass, for example. Lancaster identified two pathways by which an extra dose of estradiol from the mother can help to resolve this problem.
In one pathway, females increased the amount of estradiol to their eggs when their mate had a yellow throat. The hormone induced a barred back pattern in yellow-throated offspring. The barred pattern was not induced in non-yellow progeny.
In the other pathway, the extra hormone was prompted by an abundance of orange-throated lizards in the female's social environment. In orange-throated sons, the hormone induced a striped back pattern (suitable for an aggressive male spending lots of time in the open). Stripes were also induced in non-orange daughters. Both of these effects were inhibited by yellow genes.
"This is a classic example of an interaction between genes and environmental influences on traits," Lancaster said. "Females provide an estradiol-rich prenatal environment to their entire clutch, but different progeny respond to it in different ways depending on which genes they inherit for throat color. So a female could make some progeny barred and others from the same clutch striped, depending on what's best for each individual."
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Source:University of California - Santa Cruz