Researchers demonstrated for the first time that when reef fish parents grow up in elevated temperatures they have the ability to adjust their offspring's gender through "non-genetic and non-behavioral means."
Scientists found the mechanisms involved in offspring sex ratios are switched on during the parents' early development, instead of occurring as a result of warming waters, the University of Technology, Sydney reported.
"Understanding the ability of species to respond and cope with rising environmental temperature is key to predicting the biological consequences of global warming," said lead author and UTS Chancellor's Postdoctoral Research Fellow Jennifer Donelson.
This phenomenon could help keep sex bias in check as the oceans warm, but the study also showed that when temperatures get too warm there is a ceiling to this "transgenerational plasticity."
"It's well known that gender bias away from the optimal sex ratio of juveniles, that is roughly equal numbers of males and females, can have significant consequences for population success," Donelson said. "A reduction in the proportion of females in the population could be especially damaging because population growth rate is often constrained by female fertility."
The team found temperature increases of only 1.5 degrees Celsius above average summer temperatures could reduce the proportion of female offspring by as much as 30 percent. Despite this risk, the sex ratios were restored if the parents were raised in these warmer temperatures for their entire lives. On the other hand, at a temperature of 3.0 degrees Celsius above average this recovery did not appear to occur.
"Previous research has focused on the changes to the timing of breeding and mothers behaviourally altering the location of their nest to compensate for warming. The novelty of our study was using a multigenerational (three generations) rearing design to ask questions about non-genetic and non-behavioural parental effects to sex determination," Donelson said.
The findings were published in a recent edition of the journal Global Change Biology.
