The causes and consequences of intraspecific variation in standard metabolic rate
Lead Research Organisation:
University of Glasgow
Department Name: Institute of Biomedical & Life Sciences
Abstract
Why does substantial variation between individuals in their physiology persist, when it appears to have a significant effect on viability? One explanation for the maintenance of individual variation in a key trait is that it is non-genetic in origin and is created by environmental or maternal influences, but the direct evidence for this is often weak. This project will investigate the causes / and also the consequences / of variation between individuals in their minimal rate of metabolism, generally termed basal or standard metabolic rate (SMR). SMR varies considerably between (but is consistent within) individual animals and has major effects on performance: in salmonid fish, for example, an individual's SMR when a fry is a significant predictor of its dominance status, future growth and survival rate, as well as being a major influence on the efficiency of growth. However, the heritability of SMR is low. Why, then, is there so much phenotypic variation in SMR? Here we put forward the hypotheses that different environments favour different rates of metabolism, and that rates of metabolism are programmed by embryonic exposure to maternal steroid hormones (testosterone and cortisol) in the egg. Using trout as a study system, we will test novel predictions that arise from this hypothesis by means of experiments on both breeding adults and their offspring in a range of rearing conditions. We will test by means of hormone manipulations whether a mother's hormone levels at the time of spawning affect metabolic rates in her fry and whether eggs from different parts of the ovary receive different levels of hormone, so generating variation in metabolic rate (and aggression) within the offspring. We will also test whether the best metabolic rate (high or low) depends on the microhabitat in which the fish is living, so providing an explanation for the persistence of this variation. The information gathered will provide an understanding of the causes and consequences of variation in this basic physiological trait and of the role that hormones play as a maternal tool for adjusting offspring to the environment, so linking endocrinology, ecophysiology, behaviour and populations. The results will have relevance for studies of local adaptation and population structure, but also fish welfare and the design of husbandry regimes.
People |
ORCID iD |
Neil Metcalfe (Principal Investigator) |
Publications
Armstrong J
(2011)
Ecological consequences of variation in standard metabolism and dominance among salmon parr
in Ecology of Freshwater Fish
Burton T
(2011)
Egg hormones in a highly fecund vertebrate: do they influence offspring social structure in competitive conditions?
in Functional Ecology
Burton T
(2013)
Among-sibling differences in the phenotypes of juvenile fish depend on their location within the egg mass and maternal dominance rank.
in Proceedings. Biological sciences
Burton T
(2011)
What causes intraspecific variation in resting metabolic rate and what are its ecological consequences?
in Proceedings. Biological sciences
Dijkstra PD
(2013)
Metabolic divergence between sibling species of cichlids Pundamilia nyererei and Pundamilia pundamilia.
in Journal of fish biology
Hoogenboom MO
(2011)
Implantation of cocoa butter reduces egg and hatchling size in Salmo trutta.
in Journal of fish biology
Hoogenboom MO
(2012)
Relationship between oxidative stress and circulating testosterone and cortisol in pre-spawning female brown trout.
in Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
Description | The project showed that metabolic rate varied between individual trout, that these differences had effects on behaviour and that they arose from the eggs having been in different positions within the ovary. Hormone manipulations aimed at testing whether the differences had a hormonal cause were inconclusive. |
Exploitation Route | Work does not have an applied relevance. |
Sectors | Agriculture, Food and Drink |
Description | ERC Advanced Grant |
Amount | € 2,253,716 (EUR) |
Funding ID | 322784 |
Organisation | European Research Council (ERC) |
Sector | Public |
Country | Belgium |
Start | 05/2013 |
End | 04/2018 |
Description | Cafe Sci talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Presentation given by Neil Metcalfe on individual variation in metabolic rates to Glasgow Cafe Scientifique group of members of the public, followed by a Q & A session |
Year(s) Of Engagement Activity | 2016 |
Description | Presentation given to RAFTS meeting |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Presentation given on our research on salmon ecology to the annual meeting of UK fisheries biologists and managers |
Year(s) Of Engagement Activity | 2015 |