scholarly journals How to model honeybee population dynamics: stage structure and seasonality

2020 ◽  
pp. 1-34 ◽  
Author(s):  
Jun Chen ◽  
Komi Messan ◽  
Marisabel Rodriguez Messan ◽  
Gloria DeGrandi-Hoffman ◽  
Dingyong Bai ◽  
...  
Keyword(s):  
Age Structure ◽  
Theoretical Study ◽  
Stage Structure ◽  
Egg Laying ◽  
Life History Parameter ◽  
Honeybee Population ◽  
Honeybee Colony ◽  
Theoretical And Numerical Analysis ◽  
Parameter Values ◽  
Condition B

Western honeybees (Apis Mellifera) serve extremely important roles in our ecosystem and economics as  they are responsible for pollinating $ 215 billion dollars annually over the world.  Unfortunately,  honeybee population and their colonies have been declined dramatically. The purpose of this article is to explore how we should model honeybee population with age structure and validate the model using empirical data so that we can identify different factors that lead to the survival and healthy of the honeybee colony.  Our theoretical study combined with simulations and data validation suggests that the proper age structure incorporated in the model  and seasonality are important for modeling honeybee population.  Specifically, our work implies that the model assuming that (1) the adult bees are survived from the egg population rather than the brood population; and (2) seasonality in the queen egg laying rate, give the better fit than other honeybee models. The related theoretical and numerical analysis of the most fit model indicate that (a) the survival of honeybee colonies requires a large queen egg-laying rate and smaller values of the other life history parameter values in addition to proper initial condition; (b) both brood and adult bee populations are increasing with respect to the increase in the egg-laying rate and the decreasing in other parameter values; and (c) seasonality may promote/suppress the survival of the honeybee colony. 

scholarly journals Ensemble models for data-poor assessment: accounting for uncertainty in life-history information

2019 ◽  
Vol 76 (4) ◽  
pp. 870-883 ◽  
Author(s):  
Merrill B Rudd ◽  
James T Thorson ◽  
Skyler R Sagarese
Keyword(s):  
Life History ◽  
Learning Algorithm ◽  
Stock Assessment ◽  
Model Averaging ◽  
Biological Information ◽  
Parameter Distribution ◽  
Life History Parameter ◽  
Multivariate Distributions ◽  
Life History Parameters ◽  
Parameter Values

Abstract Length measurements from fishery catch can be used in data-limited assessments to estimate important population parameters to guide management, but results are highly sensitive to assumptions about biological information. Ideally, local life history studies inform biological parameters. In the absence of reliable local estimates, scientists and managers face the difficult task of agreeing on fixed values for life-history parameters, often leading to additional uncertainty unquantified in the assessment or indecision defaulting to status-quo management. We propose an ensemble approach for incorporating life history uncertainty into data-limited stock assessments. We develop multivariate distributions of growth, mortality, and maturity parameter values, then use bivariate interpolation and stacking as an ensemble learning algorithm to propagate uncertainty into length-based, data-limited stock assessment models. Simulation testing demonstrated that stacking across life history parameter values leads to improved interval coverage over simple model averaging or assuming the parameter distribution means when the true life-history parameter values are unknown. We then applied the stacking approach for a U.S. Caribbean stock where the Scientific and Statistical Committee did not accept the assessment due to uncertainty in life history parameters. Stacking can better characterize uncertainty in stock status whenever life-history parameters are unknown but likely parameter distributions are available.

scholarly journals Age structure is critical to the population dynamics and survival of honeybee colonies

2016 ◽  
Vol 3 (11) ◽  
pp. 160444 ◽  
Author(s):  
M. I. Betti ◽  
L. M. Wahl ◽  
M. Zamir
Keyword(s):  
Population Dynamics ◽  
Age Structure ◽  
Division Of Labour ◽  
Natural Consequence ◽  
Substantial Impact ◽  
Severity Of Disease ◽  
Bee Colony ◽  
Honeybee Colony ◽  
Age Structured ◽  
Over Time

Age structure is an important feature of the division of labour within honeybee colonies, but its effects on colony dynamics have rarely been explored. We present a model of a honeybee colony that incorporates this key feature, and use this model to explore the effects of both winter and disease on the fate of the colony. The model offers a novel explanation for the frequently observed phenomenon of ‘spring dwindle’, which emerges as a natural consequence of the age-structured dynamics. Furthermore, the results indicate that a model taking age structure into account markedly affects the predicted timing and severity of disease within a bee colony. The timing of the onset of disease with respect to the changing seasons may also have a substantial impact on the fate of a honeybee colony. Finally, simulations predict that an infection may persist in a honeybee colony over several years, with effects that compound over time. Thus, the ultimate collapse of the colony may be the result of events several years past.

scholarly journals Theoretical Study on Self-Organization of Vegetation Patterns Triggered by Water Resource in Deposited Sediment Layer

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Tousheng Huang ◽  
Huayong Zhang ◽  
Zhao Liu ◽  
Ge Pan ◽  
Xiumin Zhang ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Water Resource ◽  
Theoretical Study ◽  
Turing Instability ◽  
The Self ◽  
Self Organization ◽  
Vegetation Patterns ◽  
Sediment Layer ◽  
Spatiotemporal Model ◽  
Parameter Values

This research focuses on the self-organization of vegetation patterns on severely degraded eroding lands, triggered by water resource in the deposited sediment layer on which the vegetation patterns are formed. A nonlinear spatiotemporal model is developed with the consideration of the interactions between vegetation biomass and water resource stored in the sediment layer. With employment of the model, the conditions for pattern formation of the considered ecological system are determined via Turing instability analysis. Numerical simulations of the research demonstrate the formation of banded, labyrinth, and gapped vegetation patterns, with the parameter values taken from the literature. The characteristics of the vegetation patterns are analyzed. Comparing the characteristics of the vegetation patterns of this research with that available in literature, great similarity of pattern formation is shown. The results obtained provide a theoretical comprehension on natural vegetation restoration of severely degraded eroding lands.

NORMAL FORMS AND LORENZ ATTRACTORS

1993 ◽  
Vol 03 (05) ◽  
pp. 1123-1139 ◽  
Author(s):  
A. L. SHIL'NIKOV ◽  
L. P. SHIL'NIKOV ◽  
D. V. TURAEV
Keyword(s):  
Normal Forms ◽  
Theoretical Study ◽  
Three Dimensional ◽  
Symmetric Case ◽  
Lorenz Attractor ◽  
Lorenz Model ◽  
Main Method ◽  
New Criterion ◽  
Lorenz Attractors ◽  
Parameter Values

Normal forms for eleven cases of bifurcations of codimension-3 are considered, basically, in systems with a symmetry, which can be reduced to one of the two three-dimensional systems. The first system is the well-known Lorenz model in a special notation, the second is the Shimizu-Morioka model. In contrast with two-dimensional normal forms which admit, in principle, a complete theoretical study, in three-dimensional systems such analysis is practically impossible, except for particular parameter values when a system is close to an integrable system. Therefore, the main method of the investigation is qualitatively-numerical. In that sense, a description of principal bifurcations which lead to the appearance of the Lorenz attractor is given for the models above, and the boundaries of the regions of the existence of this attractor are selected. We pay special attention to bifurcation points corresponding to a formation of a homoclinic figure-8 of a saddle with zero saddle value and that of a homoclinic figure-8 with zero separatrix value. In L. P. Shil'nikov [1981], it was established that these points belong to the boundary of the existence of the Lorenz attractor. In the present paper, the bifurcation diagrams near such points for the symmetric case are given and a new criterion of existence of the nonorientable Lorenz is also suggested.

Dissemination of genetic improvement through a livestock industry

1971 ◽  
Vol 13 (3) ◽  
pp. 401-411 ◽  
Author(s):  
Maurice Bichard
Keyword(s):  
Age Structure ◽  
Genetic Improvement ◽  
Theoretical Study ◽  
Livestock Production ◽  
Annual Rate ◽  
Livestock Industry ◽  
Actual Size ◽  
Made In ◽  
The Way

SUMMARYA theoretical study is reported of the way in which additive genetic improvement, made in a nucleus population, is passed to successive levels in a three-tier multiplication system. The rate at which progress accumulates at each level is approximately equal. The extent to which each tier is genetically behind the previous one has been termed the ‘improvement lag’. These lags can be considerable; their actual size is determined by the annual rate of progress in the nucleus, the age structure in the lower tiers, and by the origins and degree of selection achieved in the animals used as parents in these tiers. Only improvements generated in the top tier are cumulative. The scope for reducing the improvement lag is discussed within the context of livestock production in Britain.

Habitat difference in food abundance possibly causes within-population variation in the timing of breeding in the Madagascar paradise flycatcher (Terpsiphone mutata)

2006 ◽  
Vol 84 (6) ◽  
pp. 817-822 ◽  
Author(s):  
T. Mizuta
Keyword(s):  
Environmental Factors ◽  
Age Structure ◽  
Egg Laying ◽  
Food Abundance ◽  
Dry Forest ◽  
Population Variation ◽  
Timing Of Breeding ◽  
Continuous Forest ◽  
Habitat Difference ◽  
The Difference

Within-population variation in the timing of breeding in the insectivorous Madagascar paradise flycatcher, Terpsiphone mutata (L., 1766), was investigated in a dry forest of northwestern Madagascar. The study area was divided into two sites (namely, A and B) based on the distance from the waterside. An examination was conducted to determine whether the date of egg laying varies between the two sites, and if it does vary, what are the environmental factors that affect the variation. The females started egg laying significantly earlier at site B than at site A. The two sites are located in a continuous forest; hence, photoperiod and precipitation would not differ between them. The number of insects was higher at site B than at site A. The difference in the temperature was not considered to be the cause of the variation in the date of egg laying. Age structure of the females was not likely to differ between the sites. Therefore, the variation in the date of egg laying is considered to be caused by the difference in food abundance that is associated with the relative distance from the waterside.

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