A novel study by British Scientists has indicated the enhanced environmental vulnerablility of male seagulls as compared to females, during embryonic development.
In many birds, siblings hatch at different times, resulting in age hierarchies within broods, with younger chicks often suffering reduced competitive ability and poorer survival compared to older siblings.During the last phase of incubation, birds' auditory system is developed and embryos communicate with each other by auditory stimuli.
These vocalizations may act as a cue for later-developing embryos about forthcoming competition, and there is evidence that they can respond to these cues by accelerating their hatching time, to reduce their age disadvantage. However, it is unclear whether this flexibility in developmental rates is sex-specific.
Maria Bogdanova and Ruedi Nager from the University of Glasgow in the UK experimentally manipulated the social environment of herring gull embryos and tested whether sibling contact during the embryonic stage affects the developmental rate of males and females differently, and whether this has consequences for their post-hatching performance.
The last-laid eggs - female gulls commonly lay three eggs - were incubated either alone with no information about the presence of older siblings (experimental group), or in contact with other eggs which provided information about the presence of more advanced embryos (control group, replicating natural conditions).
Post-hatching, the chicks were reared either with nest mates or alone.
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In contrast, when incubated with normal between-embryo contact, males were unable to hatch as fast and fledged in significantly poorer condition than females, regardless of whether they were reared singly or in a brood.
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The study is published in Springer's journal, Behavioral Ecology and Sociobiology.
Source-ANI
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