scholarly journals Competition in depleting resource environments shapes the thermal response of population fitness in a disease vector

2021 ◽  
Author(s):  
Paul Huxley ◽  
Kris Murray ◽  
Samraat Pawar ◽  
Lauren Cator
Keyword(s):  
Life History Traits ◽  
Natural Populations ◽  
Thermal Response ◽  
Population Level ◽  
Climatic Warming ◽  
Larval Competition ◽  
Structured Population Model ◽  
Future Studies ◽  
Disease Vector ◽  
Structured Population

Abstract Mathematical models that incorporate the temperature dependence of lab-measured life history traits are increasingly used to predict how climatic warming will affect ectotherms, including disease vectors and other arthropods. These temperature-trait relationships are typically measured under laboratory conditions that ignore how conspecific competition in depleting resource environments—a commonly occurring scenario in nature—regulates natural populations. Here, we used laboratory experiments on the mosquito Aedes aegypti, combined with a stage-structured population model, to show that intensified larval competition in ecologically-realistic depleting resource environments can significantly diminish the vector’s maximal population-level fitness across the entire temperature range, cause a 6°C decrease in the optimal temperature for fitness, and contract its thermal niche width by 10°C. Our results provide evidence for future studies to consider competition dynamics under depleting resources when predicting how eukaryotic ectotherms will respond to climatic warming.

scholarly journals DYNAMICS OF A STRUCTURED SLUG POPULATION MODEL IN THE ABSENCE OF SEASONAL VARIATION

2006 ◽  
Vol 16 (12) ◽  
pp. 1961-1985 ◽  
Author(s):  
M. A. BEES ◽  
O. ANGULO ◽  
J. C. LÓPEZ-MARCOS ◽  
D. SCHLEY
Keyword(s):  
Population Model ◽  
Life History Traits ◽  
Competitive Balance ◽  
Model Design ◽  
Structured Population Model ◽  
Size Dependent ◽  
Structured Population ◽  
Systematic Exploration ◽  
Simple Ratio ◽  
Steady State Solutions

We develop a novel, nonlinear structured population model for the slug Deroceras reticulatum, a highly significant agricultural pest of great economic impact, in both organic and non-organic settings. In the absence of seasonal variations, we numerically explore the effect of life history traits that are dependent on an individual's size and measures of population biomass. We conduct a systematic exploration of parameter space and highlight the main mechanisms and implications of model design. A major conclusion of this work is that strong size dependent predation significantly adjusts the competitive balance, leading to non-monotonic steady state solutions and slowly decaying transients consisting of distinct generational cycles. Furthermore, we demonstrate how a simple ratio of adult to juvenile biomass can act as a useful diagnostic to distinguish between predated and non-predated environments, and may be useful in agricultural settings.

scholarly journals Effects of density dependent larval competition on the life history traits of Aedes aegypti and Aedes albopictus (Diptera: Culicidae)

2017 ◽  
Vol 49 (1) ◽  
pp. 97 ◽  
Author(s):  
Sampa Banerjee ◽  
Soujita Pramanik ◽  
Soumyajit Banerjee ◽  
Goutam K. Saha ◽  
Gautam Aditya
Keyword(s):  
Life History ◽  
Aedes Aegypti ◽  
Life History Traits ◽  
Population Level ◽  
Competitive Interactions ◽  
Pupal Weight ◽  
Larval Competition ◽  
Density Dependent ◽  
Geographical Regions ◽  
F2 Generation

Consequences of larval competition at the population level provide explanation for the differences in relative abundance of <em>Aedes aegypti</em> and <em>Aedes</em> <em>albopictus</em> in different geographical regions. The outcome of competition is assessed through the estimates of the life history traits as a response to varying density and resource available for larval development. In the present study, variations in the life history traits due to density-dependent intra- and inter- specific competition involving <em>A. aegypti</em> and <em>A. albopictus</em> were assessed following the minimalist model. The instar-I larvae (0-day old F2 generation) of both <em>Aedes</em> species were reared to the adult stages using the initial rearing density of 1, 2, 4 and 6 (individuals/10ml) in multiple replicates. The age at pupation, pupal weight, adult weight and adult wing length of the individuals were considered as the response variables and surrogates of estimating the competitive interactions. Density dependent variations in the competitive interactions were evident for both the mosquitoes with reference to the selected life history traits. In <em>A. aegypti,</em> the life history traits varied with the levels of competition, which was not observed for <em>A. albopictus</em>. Although the density levels considered in the present instance were lower than in earlier studies, the observations were similar, with <em>A. albopictus</em> being competitively superior. It appears that irrespective of the density levels, interspecific competition affects <em>A. aegypti</em> and thus may bear population level consequences and overall abundance in the areas where both species are present.

scholarly journals Resonance in physiologically structured population models

2021 ◽  
Author(s):  
Kevin Gross ◽  
André M. de Roos
Keyword(s):  
Transfer Function ◽  
Frequency Spectrum ◽  
Natural Populations ◽  
Environmental Variation ◽  
Population Models ◽  
Time Model ◽  
Structured Population Model ◽  
Structured Population Models ◽  
Structured Population ◽  
Physiologically Structured Population Models

AbstractEcologists have long sought to understand how the dynamics of natural populations are affected by the environmental variation those populations experience. A transfer function is a useful tool for this purpose, as it uses linearization theory to show the frequency spectrum of the fluctuations in a population’s abundance relates to the frequency spectrum of environmental variation. Here, we show how to derive and to compute the transfer function for a continuous-time model of populations that are structured by a continuous individual-level state variable such as size. To illustrate, we derive, compute, and analyze the transfer function for a size-structured population model of stony corals with open recruitment, parameterized for a common Indo-Pacific coral species complex. This analysis identifies a sharp, multi-decade resonance driven by space competition between existing coral colonies and incoming recruits. The resonant frequency is most strongly determined by the rate at which colonies grow, and the potential for resonant oscillations is greatest when colony growth is only weakly density-dependent. While these resonant oscillations are unlikely to be predominant dynamical features of degraded reefs, they suggest the dynamical possibilities for marine invertebrates in more pristine waters. The size-structured model that we analyze is a leading example of a broader class of physiologically structured population models, and the methods we present should apply to a wide variety of models in this class.

scholarly journals Decline in the frequency and benefits of multiple brooding in great tits as a consequence of a changing environment

2009 ◽  
Vol 276 (1663) ◽  
pp. 1845-1854 ◽  
Author(s):  
Arild Husby ◽  
Loeske E.B. Kruuk ◽  
Marcel E. Visser
Keyword(s):  
Life History Traits ◽  
Parus Major ◽  
Population Level ◽  
Climatic Conditions ◽  
Long Term Study ◽  
Double Brooding ◽  
First Clutch ◽  
Second Clutch ◽  
Reproductive Events

For multiple-brooded species, the number of reproductive events per year is a major determinant of an individual's fitness. Where multiple brooding is facultative, its occurrence is likely to change with environmental conditions, and, as a consequence, the current rates of environmental change could have substantial impacts on breeding patterns. Here we examine temporal population-level trends in the proportion of female great tits ( Parus major ) producing two clutches per year (‘double brooding’) in four long-term study populations in The Netherlands, and show that the proportion of females that double brood has declined in all populations, with the strongest decline taking place in the last 30 years of the study. For one of the populations, for which we have data on caterpillar abundance, we show that the probability that a female produces a second clutch was related to the timing of her first clutch relative to the peak in caterpillar abundance, and that the probability of double brooding declined over the study period. We further show that the number of recruits from the second clutch decreased significantly over the period 1973–2004 in all populations. Our results indicate that adjustment to changing climatic conditions may involve shifts in life-history traits other than simply the timing of breeding.

scholarly journals Perspectives from animal demography on incorporating evolutionary mechanism into plant population dynamics

2018 ◽  
Author(s):  
Maria Paniw
Keyword(s):  
Environmental Change ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Population Level ◽  
Plant Population ◽  
Future Research ◽  
Phenotypic Traits ◽  
Plant Population Dynamics ◽  
Future Research Agenda ◽  
Powerful Approach

AbstractWith a growing number of long-term, individual-based data on natural populations available, it has become increasingly evident that environmental change affects populations through complex, simultaneously occurring demographic and evolutionary processes. Analyses of population-level responses to environmental change must therefore integrate demography and evolution into one coherent framework. Integral projection models (IPMs), which can relate genetic and phenotypic traits to demographic and population-level processes, offer a powerful approach for such integration. However, a rather artificial divide exists in how plant and animal population ecologists use IPMs. Here, I argue for the integration of the two sub-disciplines, particularly focusing on how plant ecologists can diversify their toolset to investigate selection pressures and eco-evolutionary dynamics in plant population models. I provide an overview of approaches that have applied IPMs for eco-evolutionary studies and discuss a potential future research agenda for plant population ecologists. Given an impending extinction crisis, a holistic look at the interacting processes mediating population persistence under environmental change is urgently needed.

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