Fairy-wren parents that sing to their developing offspring produce more attentive embryos, new Flinders University research has found.
The research published in Biology Letters found that the embryo experience of superb fairy-wrens (Malurus cyaneus) before hatching can determine the offsprings’ response to song in the egg, giving important insights into how song preference could arise.
“To our knowledge, this is the first evidence that discrimination towards particular songs, and hence potential tutors, is exhibited in the egg, well before the sensitive period believed to start only after hatching,” say Dr Diane Colombelli-Négrel and Professor Sonia Kleindorfer from the Flinders Bird Laboratory, Biological Sciences.
In one of the first studies of prenatal attentiveness to species song, Flinders University animal behaviour and evolutionary researchers have measured heart rate and other responses in tiny Australian superb fairy-wren birds as they grow from embryo to hatchling.
This is the first evidence for a prenatal physiological response to parental songs, and hence potential vocal tutors, in relation to prenatal acoustic environment.
What were once considered innate predispositions to attend to particular vocal types could in fact be learned and shaped by prenatal experience.
Flinders University researchers Dr Colombelli-Négrel and Professor Kleindorfer discover that songbird embryos are especially attentive to male song if their fathers have sung to them a lot as a developing egg.
While the thought of singing parents to their oscine eggs may conjure images of a contented family, the behaviour has significant evolutionary implications.
Until now, it has remained a mystery as to why a growing embryo would have a preference for a particular song type. ”In fact, many researchers have pre-emptively concluded that such a preference is innate,” says Professor Kleindorfer, scientific director of the Flinders Research Centre for Animal Behaviour.
“However, the new research suggests that the prenatal acoustical environment could have impacts on song preference.
“The findings indicate that cues perceived during embryonic development could influence selectivity for song tutors and that some behaviour that has previously been considered innate could be the result of embryonic experience, with implications for song dialects and divergence.
“Given that early prenatal acoustical environment impacts attentiveness to song and song is used for mate choice and species identification, this study points to the malleability of subsequent song choice that is shaped by your parental song environment.
Eggs exposed to higher parental song rate have stronger in ovo response to song compared to those exposed to lower song rate.
Embryos also demonstrated a greater response to male songs, perhaps because male songs had higher peak frequencies than female songs.
Adult males sing more than adult females during incubation, and an embryo whose father had high song rate was more attentive to male song.
More evidence is emerging from the Flinders Bird Lab that birdsong and other behaviour are learned and not inborn.
The role of acoustical environment for prenatal response and development is being examined in zebra finches by several university studies as well as similar patterns of prenatal attentiveness to species song which already has been seen in other Flinders University research work.
Prenatal environment affects embryonic response to song D. Colombelli-Négrel and S. Kleindorfer 16 August 2017 Biology Letters, Royal Society Publishing.
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