Life History Responses to Resource Variation in a Sessile Predator, The Ciliate Protozoan Tokophrya Lemnarum Stein

Kent, Elaine B.

doi:10.2307/1936703

Cited by 10 publications

(4 citation statements)

References 20 publications

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“…It feeds on Paramecium and produces one offspring for each Paramecium eaten. Kent (1981) could construct a wide range of fecundity schedules by varying the amount of food offered.…”

Section: Physiological Mechanismsmentioning

confidence: 99%

Trade-Offs in Life-History Evolution

Stearns¹

1989

Functional Ecology

2,437

2,040

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“…It feeds on Paramecium and produces one offspring for each Paramecium eaten. Kent (1981) could construct a wide range of fecundity schedules by varying the amount of food offered.…”

Section: Physiological Mechanismsmentioning

confidence: 99%

Trade-Offs in Life-History Evolution

Stearns¹

1989

Functional Ecology

2,437

2,040

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“…We further assume that resources in the current year depend on density in the previous year and climate in the current year (¢gure 1). For many species of animals, reproductive resources in the form of forage quality or physical condition of females during gestation are constrained by both density (Goulden & Hornig 1980;Kent 1981;Clutton-Brock et al 1982, 1997 and largescale climatic variation Post et al 1997. For plants, as well, availability of nutrients allocated to growth and reproduction can be limited by density of conspeci¢c and aspeci¢c competitors (Harper 1977;Wijk 1986), while soil and air temperatures constrain nutrient uptake and photosynthetic activity devoted to the accumulation of resources necessary for £owering (Shaver & Kummerow 1992;Molau 1996).…”

Section: Model Developmentmentioning

confidence: 99%

The timing of life–history events in a changing climate

Post

Forchhammer

Stenseth

et al. 2001

Proc. R. Soc. Lond. B

132

101

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Although empirical and theoretical studies suggest that climate in£uences the timing of life-history events in animals and plants, correlations between climate and the timing of events such as egg-laying, migration or £owering do not reveal the mechanisms by which natural selection operates on life-history events. We present a general autoregressive model of the timing of life-history events in relation to variation in global climate that, like autoregressive models of population dynamics, allows for a more mechanistic understanding of the roles of climate, resources and competition. We applied the model to data on 50 years of annual dates of ¢rst £owering by three species of plants in 26 populations covering 48 of latitude in Norway. In agreement with earlier studies, plants in most populations and all three species bloomed earlier following warmer winters. Moreover, our model revealed that earlier blooming re£ected increasing in£uences of resources and density-dependent population limitation under climatic warming. The insights available from the application of this model to phenological data in other taxa will contribute to our understanding of the roles of endogenous versus exogenous processes in the evolution of the timing of life-history events in a changing climate.

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“…For example, many anorexic human females do not menstruate and cannot conceive (Keys 1950). Suctorian protozoans stop reproduction upon starvation, and starved individuals live longer than fed individuals (Kent 1981). Allometric models of starvation time assume no reproduction during starvation (Threlkeld 1976, Peters 1983, Calder 1984.…”

Section: Reproduction During Starvationmentioning

confidence: 99%

Life-History Responses to Variable Environments: Starvation and Reproduction in Planktonic Rotifers

Kirk

1997

Ecology

136

100

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Zooplankton live in environments where resource abundance and quality can vary drastically over time. Success in nonequilibrium environments depends in part on the ability to store energy and control its allocation during periods of extreme food limitation or outright starvation. Starvation resistance is one measure of the ability of a species to persist when energy intake is less than energy expenditure. The life‐history responses of nine species of planktonic rotifers to food deprivation were compared using cohort life‐table experiments. Allometric patterns of energy storage and respiration rate lead to the prediction that larger species should have greater starvation resistance than smaller species. Contrary to this prediction, when rotifers were acclimated to high resource levels and starved as young adults, body mass did not predict starvation time. Rather, there was a trade‐off between survival and reproduction during starvation. Some species did not reproduce during starvation and had high starvation times (up to 5.0 d). Other species maintained or increased fecundity relative to fed controls and had low starvation times (as low as 0.4 d). Species with more rapid senescence when fed tended to have shorter starvation times. However, the interspecific trade‐off between survival and reproduction remained after removing the effect of control survivorship. Differences in life‐history responses to starvation may be critical in determining competitive outcome and community structure in variable environments. When acclimated to low food levels prior to food deprivation, simulating conditions of declining resource abundance in nature, rotifer starvation time decreased. Juveniles had longer starvation times than adults, further supporting the idea that allocating energy to reproduction decreases starvation resistance.

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Life History Responses to Resource Variation in a Sessile Predator, The Ciliate Protozoan Tokophrya Lemnarum Stein

Cited by 10 publications

References 20 publications

Trade-Offs in Life-History Evolution

Trade-Offs in Life-History Evolution

The timing of life–history events in a changing climate

Life-History Responses to Variable Environments: Starvation and Reproduction in Planktonic Rotifers

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