New paper out in Biology Letters (1)! This study, led by collaborator Dustin Owen, shows that increasing maternal levels of glucocorticoids (CORT) during gestation alters embryonic heart rates. At higher temperatures (>26˚C), embryonic heart rate in offspring of CORT-treated mothers was elevated compared to the heart rate of offspring in eggs laid by control treatment mothers. At lower temperatures, there was no difference in heart rate between embryos from the two groups. This is important and interesting, because lizard embryo development is closely tied to temperature – at temps below 26˚C, embryos are in maintenance mode only – above these temps, embryos start to develop! Increased heart rates at these higher temperatures could mean that embryos born to stressed mothers develop faster and hatch sooner (2), allowing them to escape this vulnerable life history stage in a potentially stressful environment.
Paper available here.
1) Owen, D., Sheriff, M.J., Heppner, J., Gerke, H., Ensminger, D.C., MacLeod, K.J.,Langkilde, T. Maternal corticosterone increases thermal sensitivity of heart rate in lizard embryos. Biology Letters, 15: 20180718.
2) Du W-G, Radder RS, Sun B, Shine R. 2009. Determinants of incubation period: do reptilian embryos hatch after a fixed total number of heart beats? J. Exp. Biol. 212, 1302-1306. (doi:10.1242/jeb.027425)