Factors Governing Clutch Size in Two Species of Diaptomus (Copepoda: Calanoida)

1991 ◽  
Vol 48 (3) ◽  
pp. 364-370 ◽  
Author(s):  
Patricia Chow-Fraser ◽  
Edward J. Maly
Keyword(s):  
Clutch Size ◽  
Food Limitation ◽  
Food Concentration ◽  
Interspecific Interaction ◽  
Prosome Length ◽  
Mate Availability ◽  
Chl A ◽  
Residual Variation ◽  
Freshwater Copepods ◽  
Density Population

We conducted a synoptic survey of 11 nonstratifying takes in eastern Quebec to investigate the relative importance of water temperature, food concentration ([Chl a]), female prosome length, copepod density (population and community densities), and mate availability (sex ratio and density of males) in determining the clutch size of two freshwater copepods, Diaptomus minutus and D. oregonensis. Multiple regression analyses indicated that 60% of the variation in clutch size of D. minutus could be accounted for by temperature and [Chl a] (n = 33; P = 0.0001), while 80% of the variation in the D. oregonensis data (n = 11; P = 0.0017) was explained by temperature and prosome length. Addition of other variables to either model did not significantly reduce the residual variation. We also investigated the effect of interspecific interaction on the egg-bearing potential of D. minutus and found some evidence that animals in sympatry may have lower clutch size than those in allopatry when temperature and food concentration were held constant. By using an independent measure of food and mate availability, we confirmed that clutch size decreased significantly in relation to food limitation for both species, but was unaffected by mate limitation for either.

scholarly journals Simulating the growth and distribution of planktic foraminifer using an ecophysiological multi-species model

2011 ◽  
Vol 8 (1) ◽  
pp. 1-49
Author(s):  
F. Lombard ◽  
L. Labeyrie ◽  
E. Michel ◽  
L. Bopp ◽  
E. Cortijo ◽  
...  
Keyword(s):  
Growth Rates ◽  
Food Concentration ◽  
Growth Potential ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Model Parameters ◽  
Field Observations ◽  
Lower Efficiency ◽  
Data Set ◽  
Chl A

Abstract. We present an eco-physiological model reproducing the growth of eight foraminifer species (Neogloboquadrina pachyderma, Neogloboquadrina incompta, Neogloboquadrina dutertrei, Globigerina bulloides, Globigerinoides ruber, Globigerinoides sacculifer, Globigerinella siphonifera and Orbulina universa). By using the main physiological rates of foraminifers (nutrition, respiration, symbiotic photosynthesis), this model estimates their growth as a function of temperature, light availability, and food concentration. Model parameters are directly derived or calibrated from experimental observations and only the influence of food concentration (estimated via chl-a concentration) was calibrated against field observations. Growth rates estimated from the model show positive correlation with observed abundance from plankton net data suggesting close coupling between individual and assemblage growth rates. This observation was used to directly estimate potential abundance from the model-derived growth. Using satellite data, the model simulate the dominant foraminifer with a 70.5% efficiency when compared to a data set of 576 field observations worldwide. Using outputs of a biogeochemical model of the global ocean (PISCES) instead of satellite images as forcing variables gives also good results, but with lower efficiency (58.9%). The model also correctly reproduces the relative worldwide abundance and the diversity of the eight species when compared to core tops observations both using satellite and PISCES data. This model allows prediction of the season and water depth at which each species has its highest growth potential. This offers promising perspectives for both an improved quantification of paleoceanographic reconstructions and for a better understanding of the foraminiferal role in the marine carbon cycle.

Relative food limitation drives geographical clutch size variation in South African passerines: a large-scale test of Ashmole's seasonality hypothesis

2014 ◽  
Vol 24 (4) ◽  
pp. 437-447 ◽  
Author(s):  
David Hořák ◽  
Anna Tószögyová ◽  
David Storch
Keyword(s):  
South African ◽  
Clutch Size ◽  
Large Scale ◽  
Food Limitation ◽  
Size Variation ◽  
Scale Test

Contribution of Particulate Phosphorus (> 250 μm) to the Total Phosphorus Pool in Lake Water

1984 ◽  
Vol 41 (2) ◽  
pp. 351-363 ◽  
Author(s):  
E. E. Prepas ◽  
J. Vickery
Keyword(s):  
Chlorophyll A ◽  
Total Phosphorus ◽  
Lake Water ◽  
Euphotic Zone ◽  
Particulate Phosphorus ◽  
Lake Productivity ◽  
Chl A ◽  
Relative Contribution ◽  
Residual Variation ◽  
Large Particles

Particulate phosphorus (PP) > 250 μm was concentrated in the euphotic zone of 17 lakes in central Alberta. When the euphotic zone extended below the epilimnion, PP >250 μm was concentrated deep in the euphotic zone. PP > 250 μm was a significant but variable portion of the total phosphorus (TP) pool in individual lakes; thus, samples should be collected from the euphotic zone on several dates to estimate the contribution of PP > 250 μm to the TP pool. As well, the contribution of this fraction varied among lakes: average summer values for the euphotic zone ranged from 3 to 19%. Among lakes, the contribution of large particles to the TP pool decreased proportionally as lake productivity (estimated by chlorophyll a (Chl a)) increased. The relative contribution of PP > 250 μm in summer accounted for a significant portion of the residual variation in the spring TP-summer Chl a relationship but not the summer TP-summer Chl a relationship in the study lakes. These apparently contradictory results can be explained by differences between lakes that mixed intermittently throughout the summer and those that remained permanently thermally stratified during this time.

Clutch Size of Kestrels: Seasonal Decline and Experimental Evidence for Food Limitation under Fluctuating Food Conditions

Oikos ◽  
1998 ◽  
Vol 83 (2) ◽  
pp. 259 ◽  
Author(s):  
Erkki Korpimäki ◽  
Jürgen Wiehn ◽  
Erkki Korpimaki ◽  
Jurgen Wiehn
Keyword(s):  
Experimental Evidence ◽  
Clutch Size ◽  
Food Limitation ◽  
Food Conditions ◽  
Seasonal Decline

scholarly journals Life‐history variation of a neotropical thrush challenges food limitation theory

2005 ◽  
Vol 272 (1564) ◽  
pp. 769-773 ◽  
Author(s):  
Valentina Ferretti ◽  
Paulo E Llambías ◽  
Thomas E Martin
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Clutch Size ◽  
Life History Traits ◽  
Food Limitation ◽  
Life History Evolution ◽  
Traditional Theory ◽  
Life History Variation ◽  
Nestling Growth ◽  
Parental Feeding

Since David Lack first proposed that birds rear as many young as they can nourish, food limitation has been accepted as the primary explanation for variation in clutch size and other life‐history traits in birds. The importance of food limitation in life-history variation, however, was recently questioned on theoretical grounds. Here, we show that clutch size differences between two populations of a neotropical thrush were contrary to expectations under Lack's food limitation hypothesis. Larger clutch sizes were found in a population with higher nestling starvation rate (i.e. greater food limitation). We experimentally equalized clutches between populations to verify this difference in food limitation. Our experiment confirmed greater food limitation in the population with larger mean clutch size. In addition, incubation bout length and nestling growth rate were also contrary to predictions of food limitation theory. Our results demonstrate the inability of food limitation to explain differences in several life-history traits: clutch size, incubation behaviour, parental feeding rate and nestling growth rate. These life-history traits were better explained by inter‐population differences in nest predation rates. Food limitation may be less important to life history evolution in birds than suggested by traditional theory.

Developmental Responses of Juvenile Daphnia rosea to Experimental Alteration of Temperature and Natural Seston Concentration

1981 ◽  
Vol 38 (11) ◽  
pp. 1357-1362 ◽  
Author(s):  
William E. Neill
Keyword(s):  
Food Limitation ◽  
Food Concentration ◽  
Good Survival ◽  
Oligotrophic Lakes ◽  
Poor Growth ◽  
Temperature Conditions ◽  
Development Rates ◽  
Slow Development ◽  
Survival And Growth ◽  
Daphnia Rosea

A need for accurate estimates of juvenile development rates of Daphnia rosea from oligotrophic lakes prompted this investigation into the combined effects of temperature and natural seston concentrations on growth of neonates. Significant effects of seston concentration and temperature and especially their interaction were detected upon survival, number of prereproductive instars, growth increment per instar, and duration of development. Low summertime seston concentrations that were sufficient for good survival and growth at a low rearing temperature (12 °C) generally produced high mortality, slow development, and reduced biomass increments at higher temperature (21 °C). Further, poor growth and survival under low seston – high temperature conditions were exaggerated in August compared with May, suggesting possible seasonal changes in natural seston quality and/or juvenile daphnid physiology. In contrast, higher food levels typical of springtime conditions produced excellent survival and growth regardless of the test temperature employed or season examined. Food limitation of daphnid development was thus dependent upon both temperature and food concentration within the range of conditions commonly observed in oligotrophic lakes. Extrapolation of development rates measured under only a limited range of food–temperature conditions or taken from literature values should be done cautiously.Key words: Daphnia, development, juvenile, seston, food, temperature, growth, survival, Cladocera, oligotrophic

scholarly journals Food limitation explains most clutch size variation in the Nazca booby

2001 ◽  
Vol 70 (4) ◽  
pp. 539-545 ◽  
Author(s):  
L. D. Clifford ◽  
D. J. Anderson
Keyword(s):  
Clutch Size ◽  
Food Limitation ◽  
Size Variation

scholarly journals Ancestral ecological regime shapes reaction to food limitation in the Least Killifish, Heterandria formosa

2020 ◽  
Author(s):  
Anja Felmy ◽  
Jeff Leips ◽  
Joseph Travis
Keyword(s):  
Life Histories ◽  
Food Limitation ◽  
Pathogen Transmission ◽  
High Density ◽  
Food Level ◽  
Low Density ◽  
Capita Food ◽  
Per Capita ◽  
Density Population ◽  
Density Regime

AbstractIn populations with contrasting densities of conspecifics, we often see genetically-based differences in life histories. The divergent life histories could be driven by several distinct agents of selection, including, amongst other factors, variation in per-capita food levels, the intensity of crowding-induced stress, rates of pathogen transmission, mate encounter rates, and the rates with which waste products accumulate. Understanding which selective agents act in a particular population is important as the type of agents can affect both population dynamics and evolutionary responses to density-dependent selection. Here we used a full-factorial laboratory experiment to examine whether two populations of a small live-bearing freshwater fish, characterised by high-density/low-predation or low-density/high-predation conditions, are adapted to different per-capita food levels. As expected, fish from the higher density regime handled food limitation better than those from the lower density regime. Although the lower food level resulted in slower growth, smaller body size, delayed maturation and reduced survival in both populations, especially survival to maturity showed a highly significant population x food-level interaction. At low food, 75% of fish from the low-density population died, compared to only 15% of fish from the high-density population. This difference was much smaller at high food (15% vs. 0% mortality), and was mediated, at least partly, through a larger size at birth of fish from the high-density regime. While we cannot preclude other agents of selection from operating differently in the study populations, we demonstrate that selection at higher density confers a greater ability to cope with low per-capita food availability.

Zooplankton Community Structure, but not Biomass, Influences the Phosphorus–Chlorophyll a Relationship

1984 ◽  
Vol 41 (7) ◽  
pp. 1089-1096 ◽  
Author(s):  
Michael L. Pace
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Chlorophyll A ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Similar Data ◽  
Data Set ◽  
Zooplankton Community Structure ◽  
Chl A ◽  
Residual Variation

Simultaneous observations were made of total phosphorus (TP), chlorophyll a (Chl a), and zooplankton biomass and community structure at 12 sites in the Eastern Townships (ET) region of Quebec to determine if zooplankton parameters reduced residual variation in the TP–Chl a relationship. Similar data from three stations in Lake Memphremagog and the literature were also analyzed. Zooplankton biomass was not significant in explaining residual variation in the TP–Chl a relationship of any data set studied. The mean body size of cladocerans was also not a significant additional variable in a TP–Chl a model based on the seasonal mean values in the ET lakes, but cladoceran body size was a significant factor in 13 lakes of the Indian River district of New York. The difference between these results is attributed to the rarity of large daphnids in the ET lakes. An index of zooplankton community structure derived from the slope of log abundance–log weight regressions was significant in explaining residual variation in TP–Chl a relationships for the among- and within-lake data and improved the predictive capability of TP–Chl a models. Lakes with higher concentrations of macrozooplankton relative to microzooplankton have less Chl a per unit TP. These results extend the generality of the hypothesis that large zooplankton differentially reduce Chl a relative to TP. In the ET lakes the effect of zooplankton size structure, however, was weak and this suggests that manipulation of zooplankton community structure to manage algal biomass may be of limited value in many lakes.

Experimental studies on factors limiting colonization by Daphnia pulex Leydig of coastal montane lakes in British Columbia

1978 ◽  
Vol 56 (12) ◽  
pp. 2498-2507 ◽  
Author(s):  
William E. Neill
Keyword(s):  
Water Quality ◽  
British Columbia ◽  
Large Scale ◽  
Field Experiments ◽  
Food Limitation ◽  
Experimental Studies ◽  
Daphnia Pulex ◽  
Food Concentration ◽  
Invasion Success ◽  
Limiting Factors

Laboratory and field experiments were conducted lo account for the absence of a widespread and locally abundant zooplankter Daphnia pulex From oligotrophia monlane lakes in coastal British Columbia. Water quality, food concentration, and invertebrate predation were examined as potential limiting factors. Laboratory exposure of neonate and adult D. pulex to montane take water and lowland pond water, both manipulated to the same range of seston densities, revealed significant effects of food levels and water sources. Elevated food levels consistently produced marked increases in survival, growth, and reproduction compared with natural, low seston densities. Further, enhancement effects were always lower in water from montane lakes. Laboratory predation by Chuobarux trivittutus larvae over a range of natural prey densities showed heavy predation only in the absence of normal alternative prey. Large-scale field experiments in 10 000-ℓ enclosures in a montane lake produced high invasion success by D. pulex after artificial fertilizer additions and modest invasion success in the absence of Chuoborus predation. Invasion was unsuccessful at natural seston densities when Chaoborus was present.These results suggest that food limitation, coupled with unspecified water quality effects and low levels of Chaoborus predation, limits D. pulex invasion potential, despite numerous nearby sources of dispersers.

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