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  • 1
    Electronic Resource
    Electronic Resource
    Multiple-locus heterozygosity, mortality, and growth in a cohort of Mytilus edulis (1985)
    Springer
    Marine biology 88 (1985), S. 265-271 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A positive correlation between the degree of individual heterozygosity (H) at five polymorphic enzyme loci and shell length was reported for a cohort of Mytilus edulis L. sampled in September, 1983, two months after settlement (Koehn and Gaffney, 1984). In the present study, the same cohort was resampled four and eight months after settlement in November, 1983, and April, 1984, respectively. Among individuals four months of age, there was a small, but statistically significant, negative correlation between H and shell length. In this sample, heterozygote deficiency in the cohort was less than that of any size group in the September sample. The reversal of the H-size relationship between September and November suggests that differential mortality, particularly among small, homozygous individuals, occurred in this period. For individuals eight months of age, there was no correlation between H and shell length, there was no heterozygote deficiency in the cohort and the average heterozygosity was the same as that of the largest individuals in September. At the youngest age, there was a positive relationship, between H and growth rate; as aging occurred, differential mortality altered the relationship between H and growth rate. viability differences among heterozygosity classes obscured the original effect of H on growth rate. If there is a positive relationship between heterozygosity and size, it can most likely be detected from sampling a large outbreeding population before differential mortality occurs and before energy is allocated to reproduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392588
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  • 2
    Electronic Resource
    Electronic Resource
    Food deprivation during different periods of tadpole (Hyla chrysoscelis) ontogeny affects metamorphic performance differently (1995)
    Springer
    Oecologia 103 (1995), S. 518-522 
    Details
    ISSN: 1432-1939
    Keywords: Tadpole ; Development ; Feeding ; Metamorphosis ; Starvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tadpoles in small, ephemeral pools whose duration and food content are unpredictable can potentially encounter substantial variation in diet composition and availability. We compared the effects of 10 days of food deprivation occurring early, midway and late in ontogeny on the metamorphic size and bioenergetic properties of Hyla chrysoscelis tadpoles. Tadpoles fed throughout ontogeny were controls. Metamorphs from tadpoles starved early and midway in ontogeny had the same snout-vent length and dry mass as controls, but the time to metamorphosis was extended by 8 and 19% respectively. Metamorphs of tadpoles starved late in development attained 85% of the length and 55% of the mass of controls, metamorphosed at the same time as controls, and suffered mortality 15 times greater than other treatments, perhaps because they were near the absolute minimum necessary level of energy reserves. There were no significant differences in percent organic matter, percent tissue water, condition index, and protein or glycogen concentrations between any experimental and control treatments. If food deprivation occurred early in development, the tadpoles caught up to the size of controls, but an extended developmental time would increase the risk of predation or habitat loss. If food reductions occur late in development, perhaps magnified by pond desiccation, tadpoles are stimulated to metamorphose at the same time as controls but at a smaller size. The bioenergetic composition of tadpoles at metamorphosis is unaffected by time of food deprivation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328691
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Growth, condition and specific dynamic action in the mussel Mytilus edulis recovering from starvation (1986)
    Springer
    Marine biology 93 (1986), S. 401-409 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Juvenile Mytilus edulis were grown individually in plastic racks in a tidal salt marsh for 72 d in 1984, starved in the laboratory for 130 d, and then fed the alga Isochrysis galbana daily for 64 d. Oxygen consumption was measured at various times during the course of starvation and recovery. The effects of both size (tissue dry weight) and condition (tissue size relative to shell size) on the rate of oxygen consumption during the course of starvation and recovery were analyzed by multiple regression. Weight-specific preprandial rate was inversely correlated with both size and condition. Weight-specific active rate (measured shortly after feeding) was correlated with size but not condition. Relative Scope for Activity was inversely correlated with size and positively correlated with condition. Relative Specific Dynamic Action (RSDA; the integrated physiological and mechanical response to a meal) was initially correlated negatively with size and subsequently positively with condition. Glycogen content was shown to be positively correlated with condition in mussels before starvation and during recovery. During recovery, experimental mussels returned to 90% of their estimated dry weight prior to starvation, and from 53% after starvation. At weekly intervals during recovery, oxygen consumption was measured following a meal until it returned to the preprandial rate. Both pre- and postprandial volumes (μl at STP) of oxygen consumed per hour ( $$\dot V$$ O 2pre and $$\dot V$$ O 2post , respectively) increased significantly during recovery. The postprandial rise in oxygen consumption increased significantly from 15% to 23% of $$\dot V$$ O 2pre . At the end of the recovery period, RSDA [( $$\dot V$$ O 2post − $$\dot V$$ O 2pre )/ $$\dot V$$ O 2pre ] was independent of final dry weight, but was significantly correlated with percent dry weight recovered (r 2=0.44; df=10; P〈0.02). The increase in RSDA may reflect increased utilization of food and its conversion to soma during recovery from starvation, as distinct from mechanical energy expenditure (feeding activity) following a meal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401108
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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