Aphid population dynamics: does resistance to parasitism influence population size?

It is critical to incorporate the process of population dynamics into community genetics studies to identify the mechanisms of the linkage between host plant genetics and associated communities. We studied the effects of plant genotypic diversity of tall goldenrod Solidago altissima on the population dynamics of the aphid Uroleucon nigrotuberculatum . We found genotypic variation in plant resistance to the aphid in our experiments. To determine the impact of plant genotypic diversity on aphid population dynamics, we compared aphid densities under conditions of three treatments: single-genotype plots, mixed-genotype plots and mixed-genotype-with-cages plots. In the latter treatment plants were individually caged to prevent natural enemy attack and aphid movement among plants. The synergistic effects of genotypes on population size were demonstrated by the greater aphid population size in the mixed-genotype treatment than expected from additive effects alone. Two non-exclusive hypotheses are proposed to explain this pattern. First, there is a source–sink relationship among plant genotypes: aphids move from plant genotypes where their reproduction is high to genotypes where their reproduction is low. Second, natural enemy mortality is reduced in mixed plots in a matrix of diverse plant genotypes.

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Population dynamics in northwestern China

China Population and Development Studies ◽

10.1007/s42379-021-00088-4 ◽

2021 ◽

Author(s):

Xueyan Yang ◽

Wanxin Li ◽

Wen Jing ◽

Chezhuo Gao ◽

Rui Li ◽

...

Keyword(s):

Population Dynamics ◽

Population Structure ◽

Population Size ◽

Ethnic Groups ◽

Northwestern China ◽

Average Level ◽

Han Population ◽

Sex Structure ◽

Biological Sex

AbstractThis article analyzes the population dynamics in northwestern China from roughly 2010 to 2020. The area’s dynamics showed a slow, stable increase in population size, a stable increase in the population of non-Han ethnic groups, which increased at a more rapidly than the Han population, and population rejuvenation coupled with a population structure that aged. The biological sex structure fluctuated within a balanced range in northwestern China. Urbanization advanced in northwestern China, throughout this period, but the area’s level of urbanization is still significantly lower than the average level of urbanization nationally.

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The influence of microhabitat on the population dynamics of four herbaceous species in a semiarid area of northeastern Brazil

Brazilian Journal of Biology ◽

10.1590/1519-6984.10014 ◽

2016 ◽

Vol 76 (1) ◽

pp. 45-54 ◽

Cited By ~ 2

Author(s):

K. A. Silva ◽

J. M. F. F. Santos ◽

J. R. Andrade ◽

E. N. Lima ◽

U. P. Albuquerque ◽

...

Keyword(s):

Population Dynamics ◽

Population Size ◽

Mortality Rates ◽

Dry Forest ◽

Northeastern Brazil ◽

Annual Rainfall ◽

Herbaceous Species ◽

Forest Fragment ◽

Experimental Station ◽

Over Time

Abstract Variation in annual rainfall is considered the most important factor influencing population dynamics in dry environments. However, different factors may control population dynamics in different microhabitats. This study recognizes that microhabitat variation may attenuate the influence of climatic seasonality on the population dynamics of herbaceous species in dry forest (Caatinga) areas of Brazil. We evaluated the influence of three microhabitats (flat, rocky and riparian) on the population dynamics of four herbaceous species (Delilia biflora, Commelina obliqua, Phaseolus peduncularis and Euphorbia heterophylla) in a Caatinga (dry forest) fragment at the Experimental Station of the Agronomic Research Institute of Pernambuco in Brazil, over a period of three years. D. biflora, C. obliqua and P. peduncularis were found in all microhabitats, but they were present at low densities in the riparian microhabitat. There was no record of E. heterophylla in the riparian microhabitat. Population size, mortality rates and natality rates varied over time in each microhabitat. This study indicates that different establishment conditions influenced the population size and occurrence of the four species, and it confirms that microhabitat can attenuate the effect of drought stress on mortality during the dry season, but the strength of this attenuator role may vary with time and species.

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Factors Influencing Aphid Population Dynamics and Behavior and the Consequences for Virus Spread

Advances in Disease Vector Research ◽

10.1007/978-1-4613-9044-2_2 ◽

1991 ◽

pp. 19-51 ◽

Cited By ~ 10

Author(s):

Nick Carter ◽

Richard Harrington

Keyword(s):

Population Dynamics ◽

Aphid Population ◽

Virus Spread ◽

Factors Influencing ◽

And Behavior

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POPULATION DYNAMICS OF SEX-DETERMINING ALLELES IN HONEY BEES AND SELF-INCOMPATIBILITY ALLELES IN PLANTS

Genetics ◽

10.1093/genetics/91.3.609 ◽

1979 ◽

Vol 91 (3) ◽

pp. 609-626 ◽

Cited By ~ 1

Author(s):

Shozo Yokoyama ◽

Masatoshi Nei

Keyword(s):

Population Dynamics ◽

Population Size ◽

Honey Bee ◽

Honey Bees ◽

Finite Population ◽

Large Population ◽

Allele Frequencies ◽

Self Incompatibility ◽

Overdominant Selection ◽

Incompatibility Alleles

ABSTRACT Mathematical theories of the population dynamics of sex-determining alleles in honey bees are developed. It is shown that in an infinitely large population the equilibrium frequency of a sex allele is l/n, where n is the number of alleles in the population, and the asymptotic rate of approach to this equilibrium is 2/(3n) per generation. Formulae for the distribution of allele frequencies and the effective and actual numbers of alleles that can be maintained in a finite population are derived by taking into account the population size and mutation rate. It is shown that the allele frequencies in a finite population may deviate considerably from l/n. Using these results, available data on the number of sex alleles in honey bee populations are discussed. It is also shown that the number of self-incompatibility alleles in plants can be studied in a much simpler way by the method used in this paper. A brief discussion about general overdominant selection is presented.

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A Revisit of Infinite Population Models for Evolutionary Algorithms on Continuous Optimization Problems

Evolutionary Computation ◽

10.1162/evco_a_00249 ◽

2020 ◽

Vol 28 (1) ◽

pp. 55-85

Author(s):

Bo Song ◽

Victor O.K. Li

Keyword(s):

Population Dynamics ◽

Evolutionary Algorithms ◽

Population Size ◽

Optimization Problems ◽

Continuous Optimization ◽

Analytical Framework ◽

Population Models ◽

Initial Population ◽

Infinite Population ◽

Continuous Optimization Problems

Infinite population models are important tools for studying population dynamics of evolutionary algorithms. They describe how the distributions of populations change between consecutive generations. In general, infinite population models are derived from Markov chains by exploiting symmetries between individuals in the population and analyzing the limit as the population size goes to infinity. In this article, we study the theoretical foundations of infinite population models of evolutionary algorithms on continuous optimization problems. First, we show that the convergence proofs in a widely cited study were in fact problematic and incomplete. We further show that the modeling assumption of exchangeability of individuals cannot yield the transition equation. Then, in order to analyze infinite population models, we build an analytical framework based on convergence in distribution of random elements which take values in the metric space of infinite sequences. The framework is concise and mathematically rigorous. It also provides an infrastructure for studying the convergence of the stacking of operators and of iterating the algorithm which previous studies failed to address. Finally, we use the framework to prove the convergence of infinite population models for the mutation operator and the [Formula: see text]-ary recombination operator. We show that these operators can provide accurate predictions for real population dynamics as the population size goes to infinity, provided that the initial population is identically and independently distributed.

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Consequences of barriers and changing seasonality on population dynamics and harvest of migratory ungulates

Theoretical Ecology ◽

10.1007/s12080-020-00471-w ◽

2020 ◽

Vol 13 (4) ◽

pp. 595-605

Author(s):

Bram Van Moorter ◽

Steinar Engen ◽

John M. Fryxell ◽

Manuela Panzacchi ◽

Erlend B. Nilsen ◽

...

Keyword(s):

Climate Change ◽

Population Dynamics ◽

Population Size ◽

Spatial Dynamics ◽

Infrastructure Development ◽

Negative Effects ◽

Behavioral Avoidance ◽

Animal Populations ◽

The Difference ◽

Global Threat

AbstractMany animal populations providing ecosystem services, including harvest, live in seasonal environments and migrate between seasonally distinct ranges. Unfortunately, two major sources of human-induced global change threaten these populations: climate change and anthropogenic barriers. Anthropogenic infrastructure developments present a global threat to animal migrations through increased migration mortality or behavioral avoidance. Climate change alters the seasonal and spatial dynamics of resources and therefore the effects of migration on population performance. We formulated a population model with ideal-free migration to investigate changes in population size and harvest yield due to barriers and seasonal dynamics. The model predicted an increasing proportion of migrants when the difference between areas in seasonality or carrying capacity increased. Both migration cost and behavioral avoidance of barriers substantially reduced population size and harvest yields. Not surprisingly, the negative effects of barriers were largest when the population benefited most from migration. Despite the overall decline in harvest yield from a migratory population due to barriers, barriers could result in locally increased yield from the resident population following reduced competition from migrants. Our approach and results enhance the understanding of how global warming and infrastructure development worldwide may change population dynamics and harvest offtake affecting livelihoods and rural economies.

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