Effects of Maternal Nutrition on Fat Content and Longevity of Neonates of Daphnia Magna

Cowgill, U. M.; Williams, Dinsie; Esquivel, J. B.

doi:10.2307/1548014

Cited by 68 publications

(27 citation statements)

References 10 publications

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“…High animal density leads to a shortage of available food per animal (Frank et al, 1957;Jana & Pal, 1985) and as neonates are very sensitive towards starvation (Neill, 1975;Tessier et al, 1983), they died. It has also been demonstrated that bad nutritional condition of adult animals leads to a decrease of the number of eggs per brood (Frank etal., 1957;Hall, 1964) and reduces the survival rate of eggs and neonates (Tessier & Goulden, 1982;Tessier et al, 1983;Lynch & Ennis, 1983;Cowgill et al, 1984). Also preadult animals survive less under starvation (Perrin et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

The influence of Nickel on population dynamics and on some demographic parameters of Daphnia magna

Münzinger¹

1994

Hydrobiologia

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Daphnia magna was cultured with two different techniques at sublethal nickel concentrations from 0 up to 200 jig Ni 1-. The results of the experiments run with cohorts of single individuals in static cultures were compared with the results obtained with populations held in flow through cultures. The most sensitive demographic parameters in cohorts were life span, the total number of progeny and the achievable maximum body length. The investigated nickel concentrations lowered the mean animal density in populations. Size class distribution was affected and the oscillation of the percentage of ovigorous adults increased with increasing nickel concentrations. In 200 #g Ni 1 ' one population extincted. Individuals in static cultures exposed to the same nickel concentration produced at least two neonates. Both employed techniques are discussed.

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Section: Discussionmentioning

confidence: 99%

The influence of Nickel on population dynamics and on some demographic parameters of Daphnia magna

Münzinger¹

1994

Hydrobiologia

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“…Survivorship decreases in successive clutches from the same female in the copepod Scottolana canadensis (Lonsdale 1981). In the cladoceran Daphnia magna, larval fat content and survivorship are related to maternal fat content and diet (Tessier et al 1983, Cowgill et al 1984. Thus, it is not surpnsing that age and stage alone are weak predictors of naupliar performance.…”

Section: Discussionmentioning

confidence: 99%

Molting and mortality depend on age and stage in naupliar Calanus pacificus: triplication for development time of field cohorts

López¹

1991

Mar. Ecol. Prog. Ser.

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Molting success and survivorship increased during naupliar development in the marine calanoid copepod Calanus pacificus studied in the laboratory. However, both rates decreased with age within each instar Simulations of the development of different naupliar stage I11 (NIII) age-groups suggest that mortality can shorten estimated cohort development times below the minimum possible in individual nauplii. The magnitude of this reduction depends strongly on differences in initial mortality rate among instars. The suggestion that copepod generation times in the field are independent of food availability can be reconciled with the well-established relationship between stage durations and food concentration if a distinction is made between individual and cohort development rates. Individual development rates decrease at low food levels, but with the death of a sufficiently large fraction of slowdeveloping individuals, cohort development rates may remain maximal.

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“…The fat and protein content varied according to the acclimatization period, and fat content slightly increased as temperature increased. Neutral lipids such as TAG and ST (52-59%) are the main components in D. magna, followed by more polar lipids and glycolipids (Cowgill et al 1984). The content of TAG as an energy store was maximized in juveniles and decreased during somatic growth, but recovered in adults, wherein wax ester content increased.…”

Section: Aquatic Organismsmentioning

confidence: 99%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

137

102

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The ecotoxicological assessment of pesticide effects in the aquatic environment should normally be based on a deep knowledge of not only the concentration of pesticides and metabolites found but also on the influence of key abiotic and biotic processes that effect rates of dissipation. Although the bioconcentration and bioaccumulation potentials of pesticides in aquatic organisms are conveniently estimated from their hydrophobicity (represented by log K(ow), it is still indispensable to factor in the effects of key abiotic and biotic processes on such pesticides to gain a more precise understanding of how they may have in the natural environment. Relying only on pesticide hydrophobicity may produce an erroneous environmental impact assessment. Several factors affect rates of pesticide dissipation and accumulation in the aquatic environment. Such factors include the amount and type of sediment present in the water and type of diet available to water-dwelling organisms. The particular physiological behavior profiles of aquatic organisms in water, such as capacity for uptake, metabolism, and elimination, are also compelling factors, as is the chemistry of the water. When evaluating pesticide uptake and bioconcentration processes, it is important to know the amount and nature of bottom sediments present and the propensity that the stuffed aquatic organisms have to absorb and process xenobiotics. Extremely hydrophobic pesticides such as the organochlorines and pyrethroids are susceptible to adsorb strongly to dissolved organic matter associated with bottom sediment. Such absorption reduces the bioavailable fraction of pesticide dissolved in the water column and reduces the probable ecotoxicological impact on aquatic organisms living the water. In contrast, sediment dweller may suffer from higher levels of direct exposure to a pesticide, unless it is rapidly degraded in sediment. Metabolism is important to bioconcentration and bioaccumulation processes, as is detoxification and bioactivation. Hydrophobic pesticides that are expected to be highly stored in tissues would not be bioconcentrated if susceptible to biotic transformation by aquatic organisms to more rapidly metabolized to hydrophilic entities are generally less toxic. By analogy, pesticides that are metabolized to similar entities by aquatic species surely are les ecotoxicologically significant. One feature of fish and other aquatic species that makes them more relevant as targets of environmental studies and of regulation is that they may not only become contaminated by pesticides or other chemicals, but that they constitute and important part of the human diet. In this chapter, we provide an overview of the enzymes that are capable of metabolizing or otherwise assisting in the removal of xenobiotics from aquatic species. Many studies have been performed on the enzymes that are responsible for metabolizing xenobiotics. In addition to the use of conventional biochemical methods, such studies on enzymes are increasingly being conducted using immunochemical met...

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Effects of Maternal Nutrition on Fat Content and Longevity of Neonates of Daphnia Magna

Cited by 68 publications

References 10 publications

The influence of Nickel on population dynamics and on some demographic parameters of Daphnia magna

The influence of Nickel on population dynamics and on some demographic parameters of Daphnia magna

Molting and mortality depend on age and stage in naupliar Calanus pacificus: triplication for development time of field cohorts

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

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