In many species, embryos can perceive and learn external sounds. Yet, the possibility that parents may use these embryonic capacities to alter their offspring’s developmental trajectories has not been considered. Here, we demonstrate that zebra finch parents acoustically signal high ambient temperatures (above 26°C) to their embryos. We show that exposure of embryos to these acoustic cues alone adaptively alters subsequent nestling begging and growth in response to nest temperature and influences individuals’ reproductive success and thermal preferences as adults. These findings have implications for our understanding of maternal effects, phenotypic plasticity, developmental programming, and the adaptation of endothermic species to a warming world.
[...] by acoustically signaling high ambient temperatures to their embryos before hatching, zebra finch parents can program the developmental trajectories of their offspring in response to this key environmental variable. Our findings therefore provide both an adaptive function for prenatal communication and a type of maternal effect where parental control over signal production can be unambiguously tested. By uncovering a mechanism for a transgenerational effect of temperature on development in endotherms, our study also advances our understanding of the acclimatization capacities of organisms to rising temperatures.
The animal decline might have instead been because of environmental factors such as declining atmospheric carbon dioxide and expansion of grasslands, researchers write.
"Low CO2 levels favor tropical grasses over trees, and as a consequence savannas became less woody and more open through time," John Rowan, a postdoctoral scientist from the University of Massachusetts Amherst who was involved in the research, said in a statement. "We know that many of the extinct megaherbivores fed on woody vegetation, so they seem to disappear alongside their food source."