Effect of growth compensation on subsequent physical fitness in green swordtails Xiphophorus helleri.

Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Graham Kerr Building, Glasgow G12 8QQ, UK.
Biology letters (Impact Factor: 3.35). 04/2006; 2(1):39-42. DOI: 10.1098/rsbl.2005.0414
Source: PubMed

ABSTRACT Early environmental conditions have been suggested to influence subsequent locomotor performance in a range of species, but most measurements have been of initial (baseline) performance. By manipulating early growth trajectories in green swordtail fish, we show that males that underwent compensatory growth as juveniles had a similar baseline swimming endurance when mature adults to ad libitum fed controls. However, they had a reduced capacity to increase endurance with training, which is more likely to relate to Darwinian fitness. Compensatory growth may thus result in important locomotor costs later in life.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Most animals experience temperature variations as they move through the environment. For ectotherms in particular, temperature has a strong influence on habitat choice. While well-studied at the species level, less is known about factors affecting the preferred temperature of individuals. Especially lacking is information on how physiological traits are linked to thermal preference and whether such relationships are affected by factors such feeding history and growth trajectory.This study examined these issues in the common minnow Phoxinus phoxinus, to determine the extent to which feeding history, standard metabolic rate (SMR) and aerobic scope (AS), interact to affect temperature preference.Individuals were either: 1) food-deprived for 21 days, then fed ad libitum for the next 74 days; or 2) fed ad libitum throughout the entire period. All animals were then allowed to select preferred temperatures using a shuttle-box, and then measured for SMR and AS at 10°C, estimated by rates of oxygen uptake. Activity within the shuttle-box under a constant temperature regime was also measured.In both food-deprived and control fish, SMR was negatively correlated with preferred temperature. The SMR of the food-deprived fish was elevated compared to the controls, probably due to the effects of compensatory growth, and so these growth-compensated fish preferred temperatures that were on average 2.85°C cooler than controls fed a maintenance ration throughout the study. Fish experiencing compensatory growth also displayed a large reduction in activity. In growth-compensated fish and controls, activity measured at 10°C was positively correlated with preferred temperature.Individual fish prefer temperatures that vary predictably with SMR and activity level, which are both plastic in response to feeding history and growth trajectories. Cooler temperatures probably allow individuals to reduce maintenance costs and divert more energy towards growth. A reduction in SMR at cooler temperatures, coupled with a decrease in spontaneous activity, would also allow individuals to increase surplus aerobic scope for coping with environmental stressors. In warming climates, however, aquatic ectotherms could experience frequent fluctuations in food supply with long-lasting effects on metabolic rate due to compensatory growth, while simultaneously having limited access to preferred cooler habitats.This article is protected by copyright. All rights reserved.
    Journal of Animal Ecology 05/2014; 83:1513-1522. · 4.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Determining the costs of sexual ornaments is complicated by the fact that ornaments are often integrated with other, non-sexual traits, making it difficult to dissect the effect of ornaments independent of other aspects of the phenotype. Hybridization can produce reduced phenotypic integration, allowing one to evaluate performance across a broad range of multivariate trait values. Here we assess the relationship between morphology and performance in the swordtails Xiphophorus malinche and X. birchmanni, two naturally-hybridizing fish species that differ extensively in non-sexual as well as sexual traits. We took advantage of novel trait variation in hybrids to determine if sexual ornaments incur a cost in terms of locomotor ability. For both fast-start and endurance swimming, hybrids performed at least as well as the two parental species. The sexually-dimorphic sword did not impair swimming performance per se. Rather, the sword negatively affected performance only when paired with a sub-optimal body shape. Studies seeking to quantify the costs of ornaments should consider that covariance with non-sexual traits may create the spurious appearance of costs.
    PLoS ONE 01/2014; 9(10):e109025. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Phenotypic traits are often influenced by dynamic resource allocation trade-offs which, when occurring over the course of individual lifespans, may manifest as trait aging. Although aging is studied for a variety of traits that are closely tied to reproduction or reproductive effort, the aging of multiple traits related to fitness in other ways are less well understood. We took advantage of almost 30 years of data on human whole-organism performance in the National Basketball Association (U.S.A.) to examine trends of aging in performance traits associated with scoring. Given that patterns of aging differ between sexes in other animal species, we also analysed a smaller dataset on players in the Women's National Basketball Association to test for potential sex differences in the aging of comparable traits. We tested the hypothesis that age-related changes in a specific aspect of overall performance can be compensated for by elevated expression of another, related aspect. Our analyses suggest that the aging of performance traits used in basketball is generally characterised by senescence in males, whereas age-related changes in basketball performance are less evident in females. Our data also indicate a different rate of senescence of different performance traits associated with scoring over a male's lifetime. This article is protected by copyright. All rights reserved.
    Evolution 02/2014; · 4.86 Impact Factor

Full-text (2 Sources)

Available from
Jun 10, 2014