REVIEW 3 major objections 4 minor 39 references
Antagonistic coinfection in rock-paper-scissors models during concurrent epidemics
T0 review · 3 major / 4 minor · reviewed 2026-08-15 · deepseek-v4-flash
Pith's one-line read In a spatial rock-paper-scissors model, antagonistic coinfection and mobility restriction together raise organism life expectancy by about 54%.
desk verdict Antagonistic coinfection with mobility restriction is a sensible new parameter regime in the authors' established RPS framework, but the headline 54% survival-time gain is not reproducible as written because the defining integral diverges. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The central object is a stochastic spatial rock-paper-scissors model on a square lattice with three cyclically competing species and two independent pathogens. Antagonism enters only through the death step: coinfected hosts die from disease $i$ with probability rescaled by $(1-\gamma_i)$, so $\gamma_i=1$ means a coinfected host never dies of that disease; mobility restriction $\nu$ is the probability that a randomly chosen move is refused. The metric carrying the conclusion is expected survival time $\tau=\int_0^\infty S(t)\,dt$, where $S=1-\omega$ and $\omega$ is the probability of dying in a generation from either selection or disease. This lets the paper separate infection risk, selection risk, and lifetime.
What would settle it
Run the same simulations with antagonism also modifying transmission or cure probabilities, or with a different base parameter set such as small $M$ or $T$ much larger than $S$; if the roughly 54% lifetime gain at $\gamma=\nu=1$ does not persist or reverses sign, the central quantitative claim is regime-specific rather than general.
Extended reading notes
Core claim
The central discovery is quantitative: in stochastic simulations of cyclic competition with two pathogens, rescaling coinfected-host mortality by antagonistic factors $\gamma_1,\gamma_2\in[0,1]$ lowers infection risk by up to about 26% and raises species density by up to about 11% at $\gamma_1=\gamma_2=1$, while adding a mobility-restriction factor $\nu$ reduces infection risk further and lifts expected lifetime by about 54% at $\gamma=1,\nu=1$. The authors attribute these gains to coinfected hosts living longer, which increases cure probabilities and leaves more healthy organisms arising from selection-created empty sites. They also report that global antagonism outperforms uneven antagonism by roughly a factor of two in species-density gain, and that the spatial autocorrelation length falls by about 10% as antagonism goes from zero to total.
Load-bearing premise
The results depend on antagonism acting only through a multiplicative reduction of coinfected-host disease mortality, with transmission, cure, selection, reproduction, and the base rates $S=R=1$, $M=3$, $T=4$, $C=\mu=0.1$ held fixed; if antagonism alters other steps, or the base rates differ, the reported percentages may not carry over.
Editorial extensions
If this is right
- At full antagonism but no mobility change, infection risk falls by about 26% and species density rises by about 11%, so antagonistic pathogen interactions alone may protect host populations.
- Mobility restriction alone raises expected lifetime by about 12.5% at $\gamma=0$, while with total antagonism the gain grows to about 54%, so the two effects compound rather than merely add.
- Reducing mobility by 80% cuts selection risk by about 17.5% to 22.5% depending on antagonism level, meaning movement restriction protects against competitive elimination as well as infection.
- Spatial domains become finer as antagonism strengthens, with the characteristic length scale falling about 10%, so cyclic coexistence fragments into smaller patches.
Reading between the lines
- If antagonism also altered transmission or recovery rates instead of only mortality, the reported percentages would likely change; the model's fixed parameter regime is a limitation the paper does not address.
- A testable public-health hypothesis follows: in populations where coinfecting pathogens suppress each other's virulence, movement restrictions may yield larger survival benefits than in single-pathogen settings.
- One could test robustness by sweeping $S,R,M,T,C,\mu$; the 54% figure is a single-regime result, and the qualitative claim would be stronger if the ordering of lifetime gains persists across regimes.
Signed reviews
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper studies a spatial stochastic rock-paper-scissors model with two concurrent pathogens that act antagonistically in coinfected hosts, reducing their disease-induced mortality. Using lattice simulations, the authors analyze spatial pattern formation, cure probability, infection risk, species density, and the impact of mobility restrictions on infection risk, selection risk, and expected survival time. The main quantitative claims are that antagonistic coinfection reduces infection risk by up to 26%, increases species density by up to 11%, and that combining total antagonism with full mobility restriction increases expected lifetime by approximately 54% (Fig. 10).
Significance. If the results hold, this would be a useful demonstration of how antagonistic coinfection and behavioral mobility restriction interact in a well-studied spatial competition model, with potential implications for ecological and public-health interventions. The simulation methodology is standard and transparent (100-run ensembles, standard deviations, clear interaction rules), and the study covers both global and uneven antagonism. However, the central survival-time claim is currently not reproducible because the definition of tau in Sec. 6.3 is mathematically ill-posed, and there is an internal contradiction in the reported selection-risk trend. These issues must be fixed before the paper's main contribution can be assessed.
major comments (3)
- [Section 6.3] The definition of expected survival time tau = integral_0^inf S_i dt with S_i(nu) = 1 - omega(nu) is mathematically ill-posed, because omega(nu) is a constant per-generation death probability, making the integrand constant and the integral divergent for any omega(nu) < 1. If the integral was instead evaluated only over the 5000-generation simulation window, the result depends on an arbitrary cutoff and is not an expected lifetime. The standard discrete-time estimator is tau = sum_{t>=0} (1-omega)^t = 1/omega (or tau = 1/omega in continuous time), under which the relative change satisfies tau_tilde = omega(0)/omega(nu) - 1; the reported 54% gain at gamma=1, nu=1 would then imply omega(1)/omega(0) ~ 0.65, a 35% reduction in per-generation death probability. Since the authors do not report omega(0), omega(1), or raw survival curves, Fig. 10 and the headline 54% claim are not reproducible from the stated methods. Please clarify the estimator actually used and report the underlying omega values or survival curves.
- [Section 6.2] The sentence 'we observe that the effectiveness of mobility restriction becomes more pronounced as the level of antagonism in coinfected hosts' disease mortality decreases' is directly contradicted by the numbers in the same paragraph: at nu = 0.8, the reduction in selection risk is 17.5% for gamma=0.0, 21.5% for gamma=0.5, and 22.5% for gamma=1.0, i.e., the reduction increases with antagonism, not decreases. This internal inconsistency undermines the stated conclusion about the interplay between mobility restriction and antagonism for selection risk; the text and the interpretation should be corrected.
- [Section 5 (Figs. 6-7) and Section 6.3 (Fig. 10)] All quantitative results are obtained for a single parameter regime, S=R=1, M=3, T=4, C=mu=0.1, with gamma and nu varied. The reported magnitudes (e.g., 26% infection-risk reduction, 11% density increase, 54% survival-time gain) are therefore point estimates in this regime. Since the abstract and conclusions present these percentages without caveats, please provide at least a limited sensitivity analysis (e.g., varying T or mu over an order of magnitude, or varying M) to show that the qualitative conclusions, and ideally the reported ranges, are robust. At minimum, state explicitly that the percentages are conditional on this fixed parameter set.
minor comments (4)
- [Section 5, around Fig. 5] The sentence 'the maximum rise in cure probability is approximately 5.42% for uneven antagonism and 5.95% for global antagonism, as appear in Fig. 5 for gamma = 1' is ambiguous and appears inconsistent with the later relative increases of 6.69% and 17.52% (the absolute values at gamma=1 would imply a baseline near 5.1%, below the y-axis range of Fig. 5). Please clarify whether these numbers are absolute cure probabilities at gamma=1 or absolute increases, and reconcile them with the figure.
- [Section 4, Eq. (3), and Section 6.3] The symbol S_i is used both for the spectral density in Eq. (3) and for the survival probability in Sec. 6.3; please use distinct notation.
- [Sections 3-6] Typographical issues include 'grid sites with 500 2' instead of '500^2' (Secs. 4, 5, 6.1-6.3), 'from from' in Sec. 4, 'simulations parameters' in Sec. 3, and 'Fig.10' missing a space in Sec. 6.3.
- [Section 6.1] The symbol xi_0 is used in the definition of xi_tilde but chi_0 is the notation introduced for the baseline infection risk; please standardize the notation.
Circularity Check
No circularity: the paper's quantitative claims are measured simulation outputs, not fitted or self-referential derivations.
full rationale
The paper is a forward stochastic-simulation study. The mortality rescaling by (1-gamma) is an input assumption, and the reported outputs (infection risk, cure probability, species density, selection risk, and relative survival time) are measured from the simulation ensembles rather than derived from the input by construction. No parameter is fitted to a subset of data and then renamed a prediction; the relative changes at gamma=1 and nu=1 are emergent statistics of the stochastic process. The self-citations (Refs. [28], [37], [38], [39]) supply model conventions and diagnostic definitions, but the central claims about antagonistic coinfection and mobility restriction do not reduce to those citations: no uniqueness theorem or ansatz is imported from prior work to force the numerical results. The only notable internal weakness is in Sec. 6.3, where the stated expression tau = integral_0^inf S_i dt with S_i(nu)=1-omega(nu) would diverge if omega(nu) is treated as a constant survival probability per generation; this is a definitional/reproducibility problem in the estimator, not a circularity, because the 54% figure is still reported as a simulated relative difference rather than an identity with the input mortality factors. Accordingly, no circular step meets the standard of quoting an equation that reduces to its own input, and the honest finding is no significant circularity.
Assumptions & free parameters
free parameters (8)
- S (selection rate) =
1.0
- R (reproduction rate) =
1.0
- M (mobility rate) =
3.0
- T (transmissibility) =
4.0
- C (cure rate) =
0.1
- mu (single-infection mortality) =
0.1
- gamma (antagonism factor) =
varied 0 to 1 in steps of 0.1
- nu (mobility restriction) =
varied 0 to 1 in steps of 0.1
assumptions (5)
- domain assumption May-Leonard framework with no conservation of total population (Ref. 36)
- domain assumption All species are equally susceptible to both pathogens; recovery confers no immunity; coinfection can occur at any stage
- domain assumption Antagonism acts only through mortality rescaling by (1-gamma1) and (1-gamma2)
- domain assumption Mobility restriction reduces move probability by (1-nu) uniformly
- standard math Autocorrelation and Fourier transform operations are valid on finite lattices with periodic boundaries
Cite this review
Pith. "Pith review of Antagonistic coinfection in rock-paper-scissors models during concurrent epidemics." pith.science (2026). https://pith.science/paper/S7FZUFXS
@misc{pith2026250506377,
author = {Pith},
title = {Pith review of: Antagonistic coinfection in rock-paper-scissors models during concurrent epidemics},
year = {2026},
howpublished = {\url{https://pith.science/paper/S7FZUFXS}},
note = {Machine review of arXiv:2505.06377}
}
abstract
We investigate the dynamics of dual disease epidemics within the spatial rock-paper-scissors model. In this framework, individuals from all species are equally susceptible to infection by two distinct pathogens transmitted via person-to-person contact. We assume antagonistic mortality, where the simultaneous occurrence of coinfection reduces the probability of host mortality due to complications arising from either coexisting disease. Specifically, we explore two scenarios: global antagonism, where the presence of one pathogen inhibits the progression of the other in coinfected hosts, and uneven antagonism, where only one pathogen affects the development of the other. Using stochastic simulations, we show that the characteristic length scale of the spatial patterns emerging from random initial conditions diminishes as antagonism becomes more significant. We find that antagonism enhances species population growth and reduces the average probability of healthy organisms becoming infected. Additionally, introducing individuals' mobility restrictions significantly decreases both organisms' infection risk and selection pressures. Our results demonstrate that combining mobility restrictions with antagonistic coinfection can increase organisms' life expectancy by up to $54\%$. Our findings show that integrating antagonistic coinfection and mobility restriction strategies into ecological models may provide insights into designing interventions for managing concurrent epidemics in complex systems.
Figures
Figures from the paper (4 more)
Reference graph
Works this paper leans on
-
[1]
B. Kerr, M. A. Riley, M. W. Feldman, B. J. M. Bohannan, Local dispersal promotes biodiversity in a real-life game of rock–paper–scissors, Nature 418 (2002) 171
2002
-
[2]
Durret, S
R. Durret, S. Levin, Allelopathy in spatially distributed populations, J. Theor. Biol. 185 (1997) 165–171
1997
-
[3]
B. C. Kirkup, M. A. Riley, Antibiotic-mediated antagonism leads to a bacterial game of rock-paper-scissors in vivo, Nature 428 (2004) 412– 414
2004
-
[4]
Sinervo, C
B. Sinervo, C. M. Lively, The rock-scissors-paper game and the evolution of alternative male strategies, Nature 380 (1996) 240–243
1996
-
[5]
J. B. C. Jackson, L. Buss, The rock-scissors-paper game and the evolution of alternative male strategies, Proc. Natl Acad. Sci. USA 72 (1975) 5160– 5163
1975
-
[6]
Reichenbach, M
T. Reichenbach, M. Mobilia, E. Frey, Mobility promotes and jeopardizes biodiversity in rock-paper-scissors games, Nature 448 (2007) 1046–1049
2007
-
[7]
T. Reichenbach, M. Mobilia, E. Frey, Self-organization of mobile popula- tions in cyclic competition, Journal of Theoretical Biology 254 (2) (2008) 368 – 383
work page 2008
-
[8]
Menezes, B
J. Menezes, B. Moura, T. A. Pereira, Uneven rock-paper-scissors models: Patterns and coexistence, Europhysics Letters 126 (1) (2019) 18003
2019
Show all 39 references
-
[9]
K. A. Kabir, J. Tanimoto, The role of pairwise nonlinear evolutionary dy- namics in the rock–paper–scissors game with noise, Applied Mathematics and Computation 394 (2021) 125767
2021
-
[10]
J. Park, B. Jang, Role of adaptive intraspecific competition on collective behavior in the rock–paper–scissors game, Chaos, Solitons & Fractals 171 (2023) 113448
2023
-
[11]
Barbalho, S
R. Barbalho, S. Rodrigues, M. Tenorio, J. Menezes, Ambush strategy en- hances organisms’ performance in rock–paper–scissors games, BioSys- tems 240 (2024) 105229
2024
-
[12]
Menezes, E
J. Menezes, E. Rangel, Reproduction-mobility trade-o ff in rock-paper- scissors models in changing environmental conditions, Physica Scripta 99 (4) (2024) 045235
2024
-
[13]
E. Du, E. Chen, J. Liu, C. Zheng, How do social media and individual behaviors affect epidemic transmission and control?, Science of The Total Environment 761 (2021) 144114
2021
-
[14]
A. M. Dunn, M. E. Torchin, M. J. Hatcher, P. M. Kotanen, D. M. Blumen- thal, J. E. Byers, C. A. Coon, V . M. Frankel, R. D. Holt, R. A. Hufbauer, A. R. Kanarek, K. A. Schierenbeck, L. M. Wolfe, S. E. Perkins, Indirect effects of parasites in invasions, Functional Ecology 26 (6...
2012
-
[15]
M. J. Young, N. H. Fe fferman, The dynamics of disease mediated inva- sions by hosts with immune reproductive tradeo ff, Scientific Reports 12 (2022) 4108
2022
-
[16]
Nagatani, G
T. Nagatani, G. Ichinose, K. ichi Tainaka, Epidemics of random walkers in metapopulation model for complete, cycle, and star graphs, Journal of Theoretical Biology 450 (2018) 66–75
2018
-
[17]
T. C. Reluga, Game theory of social distancing in response to an epi- demic, PLoS Comput. Biol. 6 (5) (2010) e1000793
2010
-
[18]
Stockmaier, N
S. Stockmaier, N. Stroeymeyt, S. E. C., H. D. M., L. A. Meyers, D. I. Bolnick, Infectious diseases and social distancing in nature, Science 371 (6533) (2021) eabc8881
2021
-
[19]
Stroeymeyt, A
N. Stroeymeyt, A. V . Grasse, A. Crespi, D. P. Mersch, S. Cremer, L. Keller, Social network plasticity decreases disease transmission in a eusocial insect, Science 362 (6417) (2018) 941–945
2018
-
[20]
Dimarco, G
G. Dimarco, G. Toscani, M. Zanella, Optimal control of epidemic spread- ing in the presence of social heterogeneity, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 380 (2224) (2022) 20210160
2022
-
[21]
Q. Shao, D. Han, Epidemic spreading in metapopulation networks with heterogeneous mobility rates, Applied Mathematics and Computation 412 (2022) 126559
2022
-
[22]
Edsberg Møllgaard, S
P. Edsberg Møllgaard, S. Lehmann, L. Alessandretti, Understanding com- ponents of mobility during the covid-19 pandemic, Philosophical Trans- actions of the Royal Society A: Mathematical, Physical and Engineering Sciences 380 (2214) (2022) 20210118
2022
-
[23]
T. Oka, W. Wei, D. Zhu, The e ffect of human mobility restrictions on the covid-19 transmission network in china, PLOS ONE 16 (7) (2021) 1–16
2021
-
[24]
¨Omer Faruk C ¸ aparo˘glu, Y . Ok, M. Tutam, To restrict or not to restrict? use of artificial neural network to evaluate the effectiveness of mitigation policies: A case study of turkey, Chaos, Solitons & Fractals 151 (2021) 111246
2021
-
[25]
Papanikolaou, A
V . Papanikolaou, A. Chrysovergis, V . Ragos, E. Tsiambas, S. Katsinis, A. Manoli, S. Papouliakos, D. Roukas, S. Mastronikolis, D. Peschos, A. Batistatou, E. Kyrodimos, N. Mastronikolis, From delta to omicron: S1-rbd/s2 mutation /deletion equilibrium in sars-cov-2 defined vari...
2022
-
[26]
Becerra-Flores, T
M. Becerra-Flores, T. Cardozo, Sars-cov-2 viral spike g614 mutation ex- hibits higher case fatality rate, International Journal of Clinical Practice 74 (8) (2020) e13525
2020
-
[27]
Bridier, P
A. Bridier, P. C. Piard, J-C. and, S. Labarthe, F. Dubois-Brissonnet, R. Briandet, Spatial organization plasticity as an adaptive driver of sur- face microbial communities, Front. Microbiol 8 (2017) 1364
2017
-
[28]
Menezes, E
J. Menezes, E. Rangel, Spatial dynamics of synergistic coinfection in rock-paper-scissors models, Chaos: An Interdisciplinary Journal of Non- linear Science 33 (9) (2023) 093115
2023
-
[29]
L. J. Abu-Raddad, P. Patnaik, J. G. Kublin, Dual infection with hiv and malaria fuels the spread of both diseases in sub-saharan africa, Science 314 (5805) (2006) 1603–1606
2006
-
[30]
Buckling, P
A. Buckling, P. B. Rainey, Antagonistic coevolution between a bacterium and a bacteriophage, Proceedings of the Royal Society of London. Series B: Biological Sciences 269 (1494) (2002) 931–936
2002
-
[31]
N.A., The influence of parasite infections on host immunity to co- infection with other pathogens, Front
M. N.A., The influence of parasite infections on host immunity to co- infection with other pathogens, Front. Immunol. 9 (2018) 2579
2018
-
[32]
Manna, J
S. Manna, J. McAuley, J. Jacobson, C. D. Nguyen, M. A. Ullah, I. Se- bina, V . Williamson, E. K. Mulholland, O. Wijburg, S. Phipps, C. Satzke, Synergism and antagonism of bacterial-viral coinfection in the upper res- piratory tract, mSphere 7 (1) (2022) e00984–21
2022
-
[33]
Shen, X.-Y
S.-S. Shen, X.-Y . Qu, W.-Z. Zhang, J. Li, Z.-Y . Lv, Infection against in- fection: parasite antagonism against parasites, viruses and bacteria, In- fectious Diseases of Poverty 49 (8) (2019) 126559
2019
-
[34]
F. M. Snowden, Epidemics and society: from the black death to the present, Yale University Press, New Haven and London, 2019
2019
-
[35]
Tanimoto, Sociophysics Approach to Epidemics, Springer,, Singapore, 2021
J. Tanimoto, Sociophysics Approach to Epidemics, Springer,, Singapore, 2021
2021
-
[36]
R. M. May, W. J. Leonard, Nonlinear aspects of competition between three species, SIAM J. Appl. Math. 29 (1975) 243–253
1975
-
[37]
Menezes, S
J. Menezes, S. Batista, E. Rangel, Spatial organisation plasticity reduces disease infection risk in rock–paper–scissors models, Biosystems 221 (2022) 104777
2022
-
[38]
Menezes, Mobility restrictions in response to local epidemic outbreaks in rock-paper-scissors models, Journal of Physics: Complexity 5 (1) (2024) 015018
J. Menezes, Mobility restrictions in response to local epidemic outbreaks in rock-paper-scissors models, Journal of Physics: Complexity 5 (1) (2024) 015018
2024
-
[39]
Moura, J
B. Moura, J. Menezes, Behavioural movement strategies in cyclic models, Scientific Reports 11 (2021) 6413. 9
2021
Reviewed August 15, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.