Life Science Mass Spectrometry Facility

Energy expenditure of male and female lesser black-backed gull chicks

Conditions under which embryonic development takes place can have dramatic, long-lasting fitness consequences. Poor conditions early in life may have negative effects on an individual’s phenotype, and/or influence the developmental trajectory through which the adult phenotype is attained. In the case of sexually dimorphic species, conditions during embryonic development may have different effects on male and female offspring.

In the lesser black-backed gull (Larus fuscus) it has been shown that nestling mortality is higher in males than in females. This might be related to size differences, because, as males are bigger than females, males may have higher food requirements as nestlings and therefore be more vulnerable to starvation. It is unknown however, if the reported higher nestling mortality in males is attributable to sex-differences in vulnerability to poor embryonic conditions.

This project uses an integrated approach to investigate the effects of embryonic conditions on a wide range of body functions, including energy expenditure, in male and female lesser black-backed gulls. By feeding mothers throughout the egg formation period, egg quality can be experimentally manipulated. The doubly labelled water method is used to measure energy expenditure of 10-day old male and female gull chicks, hatched from an egg of either high or low quality. The technique estimates the rate of CO2 production, taking advantage of the fact that two isotopic labels (deuterium and 18O), introduced simultaneously into the body, are eliminated at different rates. 9 September, 2005 is an important determinant of an individual’s field metabolic rate, over and above sex differences and variation in embryonic conditions.

For more details contact:

    Nanette Verboven
    Division of Environmental and Evolutionary Biology
    Institute of Biomedical and Life Sciences
    University of Glasgow.