Offspring of stressed mothers grow quicker


Australian scientists have found that stressed reef fish produce offspring that develop faster.

The study by Monica Gagliano and Mark McCormick is to be published in an upcoming issue of the journal Oecologia.

The authors studied the coral reef damselfish Pomacentrus amboinensis, in which they experimentally manipulated the exposure of fertilised eggs collected from the wild to differing levels of the stress hormone cortisol in order to determine the effects of maternal stress on offspring characteristics.

Previous studies had shown that females of this species release cortisol from their ovaries in response to environmental stress. Fish in isolated reefs with few predators or competitors show low levels of the hormone while those in high stress environments bathe their eggs in high levels of the hormone.

The authors found that high cortisol levels in P. amboinensis eggs resulted in increased egg mortality and greater asymmetry in hatchlings.

They also found that embryos developed faster in the presence of high cortisol and survived longer after hatching.

The authors consider such hormonally mediated maternal effects likely " have important repercussions on annual recruitment variability and play a key role in shaping the dynamics of future fish populations."

For more information, see the paper: Gagliano, M and MI McCormick (2009) Hormonally mediated maternal effects shape offspring survival potential in stressful environments. Oecologia doi:10.1007/s00442-009-1335-8.