Density‐dependent modulation of copepod body size and temperature–size responses in a shelf sea

2021 ◽  
Author(s):  
Stefano Corona ◽  
Andrew Hirst ◽  
David Atkinson ◽  
Angus Atkinson
Keyword(s):  
Body Size ◽  
Density Dependent ◽  
Shelf Sea

Rapid growth and large body size in annual fish populations are compromised by density‐dependent regulation

2019 ◽  
Vol 95 (2) ◽  
pp. 673-678 ◽  
Author(s):  
Milan Vrtílek ◽  
Jakub Žák ◽  
Matej Polačik ◽  
Radim Blažek ◽  
Martin Reichard
Keyword(s):  
Body Size ◽  
Rapid Growth ◽  
Large Body ◽  
Fish Populations ◽  
Large Body Size ◽  
Annual Fish ◽  
Density Dependent ◽  
Density Dependent Regulation

scholarly journals Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

2011 ◽  
Vol 278 (1721) ◽  
pp. 3142-3151 ◽  
Author(s):  
Tanya L. Russell ◽  
Dickson W. Lwetoijera ◽  
Bart G. J. Knols ◽  
Willem Takken ◽  
Gerry F. Killeen ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Population Growth ◽  
Vector Control ◽  
Anopheles Gambiae ◽  
Phenotypic Expression ◽  
Phenotypic Traits ◽  
Density Dependent ◽  
Individual Fitness ◽  
The Impact

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% w AIC c support). The individual phenotypic expression of the maternal ( p = 0.0001) and current ( p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness.

scholarly journals Social selection is density dependent but makes little contribution to total selection in New Zealand giraffe weevils

2021 ◽  
Author(s):  
David N Fisher ◽  
Rebecca J LeGrice ◽  
Christina J Painting
Keyword(s):  
Body Size ◽  
New Zealand ◽  
Evolutionary Change ◽  
The Body ◽  
Direct Selection ◽  
Social Selection ◽  
Density Dependent ◽  
Phenotypic Assortment ◽  
Body Sizes ◽  
Total Selection

AbstractSocial selection occurs when traits of interaction partners influence an individual’s fitness and can fundamentally alter total selection strength. Unlike for direct selection, however, we have little idea of what factors influence the strength of social selection. Further, social selection only contributes to overall selection when there is phenotypic assortment, but simultaneous estimates of social selection and phenotypic assortment are rare. Here we estimated social selection on body size in a wild population of New Zealand giraffe weevils (Lasiorhynchus barbicornis). We did this in a range of contexts and measured phenotypic assortment for both sexes. Social selection was mostly absent and not affected by sex ratio or the body size of the focal individual. However, at high densities selection was negative for both sexes, consistent with competitive interactions based on size for access to mates. Phenotypic assortment was also density dependent, flipping from positive at low densities to negative at high densities. However, it was always close to zero, indicating negative social selection at high densities will not greatly impede the evolution of larger body sizes. Despite its predicted importance, social selection may only influence evolutionary change in specific contexts, leaving direct selection as the dominant driver of evolutionary change.

scholarly journals Density-dependent effects of mortality on the optimal body size of a habitat shift: Why smaller is better despite increased mortality risk?

2019 ◽  
Author(s):  
P. Catalina Chaparro-Pedraza ◽  
André M. de Roos
Keyword(s):  
Body Size ◽  
Life Histories ◽  
Adaptive Dynamics ◽  
Nursery Habitat ◽  
Optimal Timing ◽  
Habitat Shift ◽  
Size Selectivity ◽  
Density Dependent ◽  
Feeding Habitat ◽  
The Rich

AbstractMany animal species across different taxa change their habitat during their development. An ontogenetic habitat shift enables the development of early vulnerable-to-predation stages in a safe ‘nursery’ habitat with reduced predation mortality, while less vulnerable stages can exploit a more risky, rich feeding habitat. Therefore, the timing of the habitat shift is crucial for individual fitness. We investigate the effect that size-selectivity in mortality in the rich feeding habitat has on the optimal timing of the habitat shift using a population model and the adaptive dynamics approach. We show that the size-selective nature of mortality in this habitat affects density-dependent body growth rate in the nursery habitat and thus the optimal timing of the habitat shift. This is caused by the effect exerted by size-dependent mortality on the size distribution of the population that results in strong competition in the nursery habitat. We furthermore find that, as a consequence of this effect, increased size-selectivity in mortality in the rich feeding habitat causes the optimal body size to shift habitat to decrease. Our results reveal the interdependence between population structure and life history traits, and highlight the need for integrating ecological interactions in the study of the evolution of life histories.

Temporal change in body mass of two sympatric hamster species and implications for population dynamics

2014 ◽  
Vol 92 (5) ◽  
pp. 389-395 ◽  
Author(s):  
Chuan Yan ◽  
Tongqin Xu ◽  
Xiaoping Cao ◽  
Fusheng Wang ◽  
Shuqing Wang ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Body Mass ◽  
Northern China ◽  
Underlying Mechanism ◽  
Growth Data ◽  
Extrinsic Factors ◽  
Factors Affecting ◽  
Density Dependent ◽  
Maximum Body

Shifting of body size distributions of animals has been a long-time focus in population ecology, but the underlying mechanism of density-dependent changes in body size and its implications for population dynamics of animals are largely unknown. In this 26-year study, we investigated intrinsic and extrinsic factors affecting body mass of the Chinese striped hamster (Cricetulus barabensis Pallas, 1773) and the greater long-tailed hamster (Tscherskia triton de Winton, 1899) in the Northern China Plain. We proposed three hypotheses to explain body mass shifts in the two hamster species: growth, survival, and reproduction hypotheses. Our results showed that mean and maximum body masses of both hamster species were positively correlated with population density, and that this density-dependent change in body mass is more likely to be caused by a change in mortality rates, not by a change in growth rates or reproduction rates. The sustained decline of body mass during the study period was probably caused by increased mortality owing to an increase in the area of agricultural irrigation. Our results suggest that, under the condition of lacking survival and growth data, the maximum body mass (which represents survival rate), minimum body mass (which represents growth rate), and mean body mass are very useful criteria in revealing intrinsic and extrinsic effects on population dynamics and the underlying mechanisms.

Bioenergetics of Stock and Recruitment

1980 ◽  
Vol 37 (6) ◽  
pp. 1012-1024 ◽  
Author(s):  
D. M. Ware
Keyword(s):  
Life History ◽  
Body Size ◽  
Optimal Foraging ◽  
Reproductive Effort ◽  
Clupea Harengus ◽  
Recruitment Curve ◽  
Density Dependent ◽  
Surplus Energy ◽  
Dependent Growth ◽  
Stock And Recruitment

A new concept of recruitment is derived from bioenergetic considerations of life history phenomena. The proposed mechanism has two components, a stock-dependent process where individual reproductive effort is a decreasing function of the abundance of the mature stock, and a density-dependent mortality process which operates during the prerecruit stage. A generalized equation describing these processes yields a family of recruitment curves which vary from being asymptotic to dome-shaped, depending on the parameter values. The theory suggests that species like Atlantic herring (Clupea harengus harengus) which tend to have small density-dependent growth coefficients and which allocate most of their surplus energy to reproduction should have a small terminal body size, a high length at maturity to L∞ ratio, and a nearly asymptotic recruitment curve. By contrast, gadoids follow a different life history strategy and therefore should have a higher L∞ and more convex recruitment function. These consequences are shown to be in accord with observed differences in L∞ and with the graded series of recruitment curves found for a wide range of marine fish stocks. From a more general viewpoint, analysis of the energy dynamics of natural populations suggests that (1) there is a real — as opposed to inferred — limit to growth, L∞, which in many species is probably determined by their reproductive effort; (2) the increase in surplus energy with body size can be linked to the theory of optimal foraging; and (3) the intensity of density-dependent growth, which influences the shape of the recruitment curve, is an increasing function of the generation time of the prey organisms of different species. Thus gadoids tend to have dome-shaped reproduction curves because they feed on slow-maturing prey, which can be overcropped by large year-classes.Key words: stock and recruitment, bioenergetics, optimal foraging, growth, reproduction, life history strategies

scholarly journals Density-dependent effects as key drivers of intraspecific size structure of six abundant fish species in lakes across Europe

2016 ◽  
Vol 73 (4) ◽  
pp. 519-534 ◽  
Author(s):  
Ignasi Arranz ◽  
Thomas Mehner ◽  
Lluís Benejam ◽  
Christine Argillier ◽  
Kerstin Holmgren ◽  
...  
Keyword(s):  
Body Size ◽  
Density Dependence ◽  
Fish Species ◽  
Size Structure ◽  
Catch Per Unit Effort ◽  
Lake Productivity ◽  
Size Spectra ◽  
Fish Size ◽  
Density Dependent ◽  
Size Diversity

We studied fish size structure by using mean size, size diversity, and the slope of linear size spectra of six common European fish species along large-scale environmental gradients. We further analyzed the response of these three size metrics to environmental variables and to density-dependent effects, i.e., relative estimates of abundance (catch per unit effort, CPUE). We found differences in the strength of main predictors of size structure between the six species, but the direction of the response was relatively similar and consistent for most of the size metrics. Mean body size was negatively related to temperature for perch (Perca fluviatilis), roach (Rutilus rutilus), and ruffe (Gymnocephalus cernuus). Lake productivity (expressed as total phosphorus concentration) and lake depth were also predictors of size structure for four of six species. Moreover, we found a strong density dependence of size structure for all species, resulting in lower mean body size and size diversity and steeper size spectra slopes when density dependence increases. This suggests that density dependence is a key driver of fish size structure.

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