scholarly journals Host phenology can select for multiple stable parasite virulence strategies

2021 ◽  
Author(s):  
Hannelore MacDonald ◽  
Dustin Brisson
Keyword(s):  
Mathematical Model ◽  
Activity Patterns ◽  
Activity Period ◽  
Parasite Transmission ◽  
Evolutionarily Stable Strategies ◽  
Geographic Locations ◽  
Seasonal Environment ◽  
Host Phenology ◽  
Evolutionary Consequences ◽  
Evolutionarily Stable

Host phenology is an important driver of parasite transmission and evolution. In a seasonal environment, monocyclic, obligate-killer parasites evolve optimal virulence strategies such that all parasite progeny are released near the end of the host season to limit parasite progeny death in the environment. It is unclear whether host seasonality imposes different constraints on polycyclic parasites such that both polycyclic and monocyclic parasites are maintained. We develop a mathematical model of a disease system with seasonal host activity to study the evolutionary consequences of host phenology on polycyclic, obligate-killer parasite virulence strategies. Seasonal host activity patterns create both monocyclic and polycyclic parasite evolutionarily stable strategies (ESS) separated by less-fit strategies (evolutionary repellors). The ESS that evolves in each system is a function of the virulence strategy of the parasite introduced into the system. The trait value for both monocyclic and polycyclic strategies is determined by two aspects of host phenology: the duration of the host activity period and the distribution in the time at which hosts first become active within each season. Longer host activity periods and more synchronous host emergence drive both the monocyclic and polycyclic strategies towards lower virulence. The results demonstrate that host phenology can, in theory, maintain diverse parasite strategies among isolated geographic locations.

scholarly journals The role of host phenology for parasite transmission

2020 ◽  
Author(s):  
Hannelore MacDonald ◽  
Erol Akçay ◽  
Dustin Brisson
Keyword(s):  
Species Interactions ◽  
Activity Period ◽  
Parasite Transmission ◽  
Nymphal Stage ◽  
Mouse Population ◽  
Tick Activity ◽  
Contact Rates ◽  
Wide Range ◽  
Host Phenology ◽  
Host Parasite

Abstract Phenology is a fundamental determinant of species distributions, abundances, and interactions. In host–parasite interactions, host phenology can affect parasite fitness due to the temporal constraints it imposes on host contact rates. However, it remains unclear how parasite transmission is shaped by the wide range of phenological patterns observed in nature. We develop a mathematical model of the Lyme disease system to study the consequences of differential tick developmental-stage phenology for the transmission of B. burgdorferi. Incorporating seasonal tick activity can increase B. burgdorferi fitness compared to continuous tick activity but can also prevent transmission completely. B. burgdorferi fitness is greatest when the activity period of the infectious nymphal stage slightly precedes the larval activity period. Surprisingly, B. burgdorferi is eradicated if the larval activity period begins long after the end of nymphal activity due to a feedback with mouse population dynamics. These results highlight the importance of phenology, a common driver of species interactions, for the fitness of a parasite.

scholarly journals The role of host phenology for parasite transmission

2019 ◽  
Author(s):  
Hannelore MacDonald ◽  
Erol Akçay ◽  
Dustin Brisson
Keyword(s):  
Species Interactions ◽  
Activity Period ◽  
Parasite Transmission ◽  
Nymphal Stage ◽  
Mouse Population ◽  
Tick Activity ◽  
Contact Rates ◽  
Wide Range ◽  
Host Phenology ◽  
Host Parasite

AbstractPhenology is a fundamental determinant of species distributions, abundances, and interactions. In host-parasite interactions, host phenology can affect parasite fitness due to the temporal constraints it imposes on host contact rates. However, it remains unclear how parasite transmission is shaped by the wide range of phenological patterns observed in nature. We develop a mathematical model of the Lyme disease system to study the consequences of differential tick developmental-stage phenology for the transmission of B. burgdorferi. Incorporating seasonal tick activity can increase B. burgdorferi fitness compared to continuous tick activity but can also prevent transmission completely. B. burgdorferi fitness is greatest when the activity period of the infectious nymphal stage slightly precedes the larval activity period. Surprisingly, B. burgdorferi is eradicated if the larval activity period begins long after the end of nymphal activity due to a feedback with mouse population dynamics. These results highlight the importance of phenology, a common driver of species interactions, for the fitness of a parasite.

MODELING SELECTION AND EXTINCTION MECHANISMS OF BIOLOGICAL SYSTEMS

2011 ◽  
Vol 22 (07) ◽  
pp. 669-686 ◽  
Author(s):  
ADIL AMIRJANOV
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Analytical Solution ◽  
Biological Systems ◽  
Selection Mechanism ◽  
Evolutionarily Stable Strategies ◽  
Animal Group ◽  
Theoretical Predictions ◽  
Evolutionarily Stable ◽  
Good Agreement

In this paper, the behavior of a genetic algorithm is modeled to enhance its applicability as a modeling tool of biological systems. A new description model for selection mechanism is introduced which operates on a portion of individuals of population. The extinction and recolonization mechanism is modeled, and solving the dynamics analytically shows that the genetic drift in the population with extinction/recolonization is doubled. The mathematical analysis of the interaction between selection and extinction/recolonization processes is carried out to assess the dynamics of motion of the macroscopic statistical properties of population. Computer simulations confirm that the theoretical predictions of described models are in good approximations. A mathematical model of GA dynamics was also examined, which describes the anti-predator vigilance in an animal group with respect to a known analytical solution of the problem, and showed a good agreement between them to find the evolutionarily stable strategies.

scholarly journals Host phenology drives the evolution of intermediate parasite virulence

2021 ◽  
Author(s):  
Hannelore MacDonald ◽  
Erol Akçay ◽  
Dustin Brisson
Keyword(s):  
Common Factor ◽  
Ecological Factors ◽  
Current Theory ◽  
Activity Period ◽  
Trade Off ◽  
Natural Systems ◽  
Virulence Evolution ◽  
Trade Offs ◽  
Host Phenology ◽  
Evolutionary Consequences

1AbstractMechanistic trade-offs between transmission and virulence are the foundation of current theory on the evolution of parasite virulence. Empirical evidence supporting these trade-offs in natural systems remains elusive, suggesting other factors could drive virulence evolution in the absence of a mechanistic trade-off. Several ecological factors modulate the optimal virulence strategies predicted from mechanistic trade-off models but none have been sufficient to explain the intermediate virulence strategies observed in most natural systems. The timing of seasonal activities, or phenology, is a common factor that influences the types and impact of many ecological interactions but is rarely considered in virulence evolution studies. We develop a mathematical model of a disease system with seasonal host activity to study the evolutionary consequences of host phenology on parasite virulence. Seasonal host activity is sufficient to drive the evolution of intermediate parasite virulence in the absence of traditional mechanistic trade-offs. The optimal virulence strategy is determined by both the duration of the host activity period as well as the variation in the host emergence timing. Parasites with low virulence strategies are favored in environments with long host activity periods and in environments in which all hosts emerge synchronously. These results demonstrate that host phenology may be sufficient, in the absence of mechanistic trade-offs, to select for intermediate optimal virulence strategies in some natural systems.

scholarly journals Evolutionary Stability for Interactions among Kin under Quantitative Inheritance.

Genetics ◽  
1989 ◽  
Vol 121 (4) ◽  
pp. 877-889
Author(s):  
A B Harper
Keyword(s):  
Inclusive Fitness ◽  
Fitness Function ◽  
Quantitative Inheritance ◽  
Evolutionarily Stable Strategies ◽  
Environmental Variance ◽  
Pairwise Interactions ◽  
Simplifying Assumptions ◽  
Multilocus Model ◽  
Evolutionarily Stable

Abstract The theory of evolutionarily stable strategies (ESS) predicts the long-term evolutionary outcome of frequency-dependent selection by making a number of simplifying assumptions about the genetic basis of inheritance. I use a symmetrized multilocus model of quantitative inheritance without mutation to analyze the results of interactions between pairs of related individuals and compare the equilibria to those found by ESS analysis. It is assumed that the fitness changes due to interactions can be approximated by the exponential of a quadratic surface. The major results are the following. (1) The evolutionarily stable phenotypes found by ESS analysis are always equilibria of the model studied here. (2) When relatives interact, one of the two conditions for stability of equilibria differs between the two models; this can be accounted for by positing that the inclusive fitness function for quantitative characters is slightly different from the inclusive fitness function for characters determined by a single locus. (3) The inclusion of environmental variance will in general change the equilibrium phenotype, but the equilibria of ESS analysis are changed to the same extent by environmental variance. (4) A class of genetically polymorphic equilibria occur, which in the present model are always unstable. These results expand the range of conditions under which one can validly predict the evolution of pairwise interactions using ESS analysis.

Conditions for evolutionarily stable strategies

1980 ◽  
Vol 17 (2) ◽  
pp. 559-562 ◽  
Author(s):  
Andris Abakuks
Keyword(s):  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Evolutionarily Stable Strategies ◽  
Necessary And Sufficient ◽  
Evolutionarily Stable

It is pointed out that the conditions given by Haigh (1975) for finding evolutionarily stable strategies corresponding to a given matrix are sufficient, but not always necessary. An example is given, and an amended version of the necessary and sufficient conditions is stated.

On Evolutionarily Stable Strategies

2021 ◽  
Author(s):  
Xiao Zhang ◽  
Yaqi Hao ◽  
Daizhan Cheng
Keyword(s):  
Evolutionarily Stable Strategies ◽  
Evolutionarily Stable

scholarly journals Daily activity of four tropical intertidal hermit crabs from Southeastern Brazil

2003 ◽  
Vol 63 (3) ◽  
pp. 537-544 ◽  
Author(s):  
A. Turra ◽  
M. R. Denadai
Keyword(s):  
High Activity ◽  
Activity Pattern ◽  
Daily Activity ◽  
Activity Patterns ◽  
High Tide ◽  
Hermit Crabs ◽  
Activity Period ◽  
Southeastern Brazil ◽  
Intertidal Flat ◽  
Circadian Activity

This study describes the daily activity in a simulated high tide situation of four species of hermit crabs (Pagurus criniticornis, Clibanarius antillensis, C. sclopetarius, and C. vittatus) that coexist in an intertidal flat in southeastern Brazil. Observations were done in two-hour intervals during two subsequent days (48 h) in three replicate pools with thirty crabs each. Among species (between and within genera) there was an evident variation in activity patterns, of which three could be distinguished. The circadian activity patterns of C. antillensis and C. vittatus could be characterized as evening and nocturnal, with resting peaks during the morning and afternoon. The circadian activity pattern of C. sclopetarius was characterized by two marked peaks of inactivity, corresponding to dawn and evening, which could represent an intrinsic association with the semi-lunar tidal cycles of the study area. Pagurus criniticornis showed high activity not influenced by day/night conditions during the entire observed period. These activity pattern variations of the studied hermit crabs should be taken into account in designing further experiments. More precise and accurate interspecific behavioral comparisons among species could be achieved in nocturnal experiments, the high activity period of all species.

Sign in / Sign up

Export Citation Format

Share Document