This post was co-written by Maria Jaramillo, an undergraduate in Michele Johnson’s lab at Trinity University.
A mother’s experience during gravidity may alter her offspring’s development, particularly through altering hormone levels in the yolk of her eggs. Stress hormones such as corticosterone (CORT) alter various aspects of offspring phenotype following in ovo exposure, and physical exercise elevates CORT in many vertebrates. In the work he presented at SICB, Jerry Husak and colleagues used exercise and food restriction to manipulate female Anolis carolinensis CORT, and to then determine whether the increased CORT was transferred to the females’ egg yolks.
Jerry assigned females to one of four treatments with different combinations of exercise and food restriction: 1) no exercise, regular diet; 2) no exercise, restricted diet; 3) exercise, regular diet; and 4) exercise, restricted diet. He found that maternal exercise increased maternal CORT (as expected), but surprisingly did not result in higher CORT in the eggs. Further, diet restriction did not affect maternal CORT, but moms with restricted diets laid eggs with reduced CORT.
This study suggests that anole mothers may manipulate the environments of their eggs in ways we don’t yet understand – the mechanisms by which CORT is transferred to eggs is an area ripe for future study!